SERVER-32691 Add write_concern_majority_passthrough.yml test suite.

Reverts to emulating the write concern to work around how prior to
MongoDB 3.4, operations that did writes didn't necessarily accept a
writeConcern object.

Also limits the usage of replica set connection strings to only the
write_concern_majority_passthrough.yml test suite to work around the
lack of complete support of MongoURI parsing in versions of the mongo
shell prior to MongoDB 3.4.

(cherry picked from commit 264d971842cffdf8b4f80def1d90241f132345b7)

41 files changed, 558 insertions, 149 deletions

diff --git a/buildscripts/resmokeconfig/suites/write_concern_majority_passthrough.yml b/buildscripts/resmokeconfig/suites/write_concern_majority_passthrough.yml
new file mode 100644
index 00000000000..b20f6790f9f
--- /dev/null
+++ b/buildscripts/resmokeconfig/suites/write_concern_majority_passthrough.yml
@@ -0,0 +1,93 @@
+test_kind: js_test
+
+selector:
+  js_test:
+    roots:
+    - jstests/core/**/*.js
+    exclude_files:
+    # These tests are not expected to pass with replica-sets:
+    - jstests/core/dbadmin.js
+    - jstests/core/opcounters_write_cmd.js
+    - jstests/core/read_after_optime.js
+    - jstests/core/capped_update.js
+    # These tests do not expect the mongo shell to be using a replica set connection string.
+    - jstests/core/bench_test*.js
+    - jstests/core/connection_string_validation.js
+    # The bypass_doc_validation.js test runs an applyOps command that causes the primary to generate
+    # an oplog entry without having applied the write. We skip this test to avoid causing a dbhash
+    # mismatch.
+    - jstests/core/bypass_doc_validation.js
+    # These tests use DBCommandCursor which doesn't correctly route getMore and killCursors
+    # commands to the original server the cursor was established on (prior to SERVER-23219).
+    - jstests/core/find_getmore_bsonsize.js
+    - jstests/core/find_getmore_cmd.js
+    - jstests/core/getmore_cmd_maxtimems.js
+    - jstests/core/kill_cursors.js
+    - jstests/core/list_collections1.js
+    - jstests/core/list_indexes.js
+    # These tests attempt to read from the "system.profile" collection, which may be missing entries
+    # if a write was performed on the primary of the replica set instead.
+    - jstests/core/*profile*.js
+    # The shellkillop.js test spawns a parallel shell without using startParallelShell() and
+    # therefore doesn't inherit the w="majority" write concern when performing its writes.
+    - jstests/core/shellkillop.js
+    exclude_with_any_tags:
+    ##
+    # The next three tags correspond to the special errors thrown by the
+    # set_read_and_write_concerns.js override when it refuses to replace the readConcern or
+    # writeConcern of a particular command. Above each tag are the message(s) that cause the tag to
+    # be warranted.
+    ##
+    # "Cowardly refusing to override read concern of command: ..."
+    - assumes_read_concern_unchanged
+    # "Cowardly refusing to override write concern of command: ..."
+    - assumes_write_concern_unchanged
+    # "Cowardly refusing to run test with overridden write concern when it uses a command that can
+    #  only perform w=1 writes: ..."
+    - requires_eval_command
+    ##
+    # The next two tags corresponds to the special error thrown by the
+    # set_read_preference_secondary.js override when it refuses to replace the readPreference of a
+    # particular command. Above each tag are the message(s) that cause the tag to be warranted.
+    ##
+    # "Cowardly refusing to override read preference of command: ..."
+    # "Cowardly refusing to run test with overridden read preference when it reads from a
+    #  non-replicated collection: ..."
+    - assumes_read_preference_unchanged
+    # "Cowardly refusing to a run a test that starts a parallel shell because prior to MongoDB 3.4
+    #  replica set connections couldn't be used in it."
+    - requires_parallel_shell
+
+executor:
+  js_test:
+    config:
+      shell_options:
+        global_vars:
+          TestData:
+            defaultReadConcernLevel: local
+        eval: >-
+          testingReplication = true;
+          load('jstests/libs/override_methods/set_read_and_write_concerns.js');
+          load('jstests/libs/override_methods/set_read_preference_secondary.js');
+        # We use --readMode=legacy because until MongoDB 3.4, DBCommandCursor wouldn't route the
+        # getMore and killCursors operations to the original server the cursor was established on.
+        readMode: legacy
+      use_connection_string: true
+    hooks:
+    # The CheckReplDBHash hook waits until all operations have replicated to and have been applied
+    # on the secondaries, so we run the ValidateCollections hook after it to ensure we're
+    # validating the entire contents of the collection.
+    - class: CheckReplDBHash
+    - class: ValidateCollections
+    - class: CleanEveryN
+      n: 20
+    fixture:
+      class: ReplicaSetFixture
+      mongod_options:
+        set_parameters:
+          enableTestCommands: 1
+      # This suite requires w="majority" writes to be applied on all secondaries. By using a 2-node
+      # replica set and having secondaries vote, the majority of the replica set is all nodes.
+      num_nodes: 2
+      voting_secondaries: true
+      use_replica_set_connection_string: true
diff --git a/buildscripts/resmokelib/core/programs.py b/buildscripts/resmokelib/core/programs.py
index 5c5f27d06c2..e1a603e4e70 100644
--- a/buildscripts/resmokelib/core/programs.py
+++ b/buildscripts/resmokelib/core/programs.py
@@ -115,7 +115,8 @@ def mongos_program(logger, executable=None, process_kwargs=None, **kwargs):
     return _process.Process(logger, args, **process_kwargs)
 
 
-def mongo_shell_program(logger, executable=None, filename=None, process_kwargs=None, **kwargs):
+def mongo_shell_program(logger, executable=None, connection_string=None, filename=None,
+                        process_kwargs=None, **kwargs):
     """
     Returns a Process instance that starts a mongo shell with arguments
     constructed from 'kwargs'.
@@ -181,9 +182,22 @@ def mongo_shell_program(logger, executable=None, filename=None, process_kwargs=N
     if config.SHELL_WRITE_MODE is not None:
         kwargs["writeMode"] = config.SHELL_WRITE_MODE
 
+    if connection_string is not None:
+        # The --host and --port options are ignored by the mongo shell when an explicit connection
+        # string is specified. We remove these options to avoid any ambiguity with what server the
+        # logged mongo shell invocation will connect to.
+        if "port" in kwargs:
+            kwargs.pop("port")
+
+        if "host" in kwargs:
+            kwargs.pop("host")
+
     # Apply the rest of the command line arguments.
     _apply_kwargs(args, kwargs)
 
+    if connection_string is not None:
+        args.append(connection_string)
+
     # Have the mongos shell run the specified file.
     args.append(filename)
 
diff --git a/buildscripts/resmokelib/testing/fixtures/interface.py b/buildscripts/resmokelib/testing/fixtures/interface.py
index 8921aa1159c..98b6fd70f17 100644
--- a/buildscripts/resmokelib/testing/fixtures/interface.py
+++ b/buildscripts/resmokelib/testing/fixtures/interface.py
@@ -60,13 +60,22 @@ class Fixture(object):
         """
         return True
 
-    def get_connection_string(self):
+    def get_internal_connection_string(self):
         """
         Returns the connection string for this fixture. This is NOT a
         driver connection string, but a connection string of the format
         expected by the mongo::ConnectionString class.
         """
-        raise NotImplementedError("get_connection_string must be implemented by Fixture subclasses")
+        raise NotImplementedError(
+            "get_internal_connection_string must be implemented by Fixture subclasses")
+
+    def get_driver_connection_url(self):
+        """
+        Return the mongodb connection string as defined here:
+        https://docs.mongodb.com/manual/reference/connection-string/
+        """
+        raise NotImplementedError(
+            "get_driver_connection_url must be implemented by Fixture subclasses")
 
     def __str__(self):
         return "%s (Job #%d)" % (self.__class__.__name__, self.job_num)
diff --git a/buildscripts/resmokelib/testing/fixtures/masterslave.py b/buildscripts/resmokelib/testing/fixtures/masterslave.py
index 2bcd3c5d6d2..41463c0d421 100644
--- a/buildscripts/resmokelib/testing/fixtures/masterslave.py
+++ b/buildscripts/resmokelib/testing/fixtures/masterslave.py
@@ -5,7 +5,6 @@ Master/slave fixture for executing JSTests against.
 from __future__ import absolute_import
 
 import os.path
-import socket
 
 import pymongo
 
@@ -160,6 +159,12 @@ class MasterSlaveFixture(interface.ReplFixture):
         mongod_options = self.mongod_options.copy()
         mongod_options.update(self.slave_options)
         mongod_options["slave"] = ""
-        mongod_options["source"] = "%s:%d" % (socket.gethostname(), self.port)
+        mongod_options["source"] = self.master.get_internal_connection_string()
         mongod_options["dbpath"] = os.path.join(self._dbpath_prefix, "slave")
         return self._new_mongod(mongod_logger, mongod_options)
+
+    def get_internal_connection_string(self):
+        return self.master.get_internal_connection_string()
+
+    def get_driver_connection_url(self):
+        return self.master.get_driver_connection_url()
diff --git a/buildscripts/resmokelib/testing/fixtures/replicaset.py b/buildscripts/resmokelib/testing/fixtures/replicaset.py
index b47898e8d9e..a32198b8357 100644
--- a/buildscripts/resmokelib/testing/fixtures/replicaset.py
+++ b/buildscripts/resmokelib/testing/fixtures/replicaset.py
@@ -30,7 +30,9 @@ class ReplicaSetFixture(interface.ReplFixture):
                  preserve_dbpath=False,
                  num_nodes=2,
                  auth_options=None,
-                 replset_config_options=None):
+                 replset_config_options=None,
+                 voting_secondaries=False,
+                 use_replica_set_connection_string=False):
 
         interface.ReplFixture.__init__(self, logger, job_num)
 
@@ -40,6 +42,8 @@ class ReplicaSetFixture(interface.ReplFixture):
         self.num_nodes = num_nodes
         self.auth_options = auth_options
         self.replset_config_options = utils.default_if_none(replset_config_options, {})
+        self.voting_secondaries = voting_secondaries
+        self.use_replica_set_connection_string = use_replica_set_connection_string
 
         # The dbpath in mongod_options is used as the dbpath prefix for replica set members and
         # takes precedence over other settings. The ShardedClusterFixture uses this parameter to
@@ -78,10 +82,13 @@ class ReplicaSetFixture(interface.ReplFixture):
         # Initiate the replica set.
         members = []
         for (i, node) in enumerate(self.nodes):
-            member_info = {"_id": i, "host": node.get_connection_string()}
+            member_info = {"_id": i, "host": node.get_internal_connection_string()}
             if i > 0:
                 member_info["priority"] = 0
-                member_info["votes"] = 0
+                if i >= 7 or not self.voting_secondaries:
+                    # Only 7 nodes in a replica set can vote, so the other members must still be
+                    # non-voting when this fixture is configured to have voting secondaries.
+                    member_info["votes"] = 0
             members.append(member_info)
         initiate_cmd_obj = {"replSetInitiate": {"_id": self.replset_name, "members": members}}
 
@@ -182,9 +189,23 @@ class ReplicaSetFixture(interface.ReplFixture):
 
         return logging.loggers.new_logger(logger_name, parent=self.logger)
 
-    def get_connection_string(self):
+    def get_internal_connection_string(self):
         if self.replset_name is None:
-            raise ValueError("Must call setup() before calling get_connection_string()")
+            raise ValueError("Must call setup() before calling get_internal_connection_string()")
 
-        conn_strs = [node.get_connection_string() for node in self.nodes]
+        conn_strs = [node.get_internal_connection_string() for node in self.nodes]
         return self.replset_name + "/" + ",".join(conn_strs)
+
+    def get_driver_connection_url(self):
+        if self.replset_name is None:
+            raise ValueError("Must call setup() before calling get_driver_connection_url()")
+
+        if self.use_replica_set_connection_string:
+            # The mongo shell requires the database name when specifying a replica set connection
+            # string, so we hardcode "test" because that's the default database anyway.
+            conn_strs = [node.get_internal_connection_string() for node in self.nodes]
+            return "mongodb://" + ",".join(conn_strs) + "/test?replicaSet=" + self.replset_name
+        else:
+            # We return a direct connection to the expected pimary when only the first node is
+            # electable because we want the client to error out if a stepdown occurs.
+            return self.nodes[0].get_driver_connection_url()
diff --git a/buildscripts/resmokelib/testing/fixtures/shardedcluster.py b/buildscripts/resmokelib/testing/fixtures/shardedcluster.py
index 282319a235c..d45ed2cfa01 100644
--- a/buildscripts/resmokelib/testing/fixtures/shardedcluster.py
+++ b/buildscripts/resmokelib/testing/fixtures/shardedcluster.py
@@ -170,6 +170,15 @@ class ShardedClusterFixture(interface.Fixture):
                 all(shard.is_running() for shard in self.shards) and
                 self.mongos is not None and self.mongos.is_running())
 
+    def get_internal_connection_string(self):
+        if self.mongos is None:
+            raise ValueError("Must call setup() before calling get_internal_connection_string()")
+
+        return self.mongos.get_internal_connection_string()
+
+    def get_driver_connection_url(self):
+        return "mongodb://" + self.get_internal_connection_string()
+
     def _new_configsvr(self):
         """
         Returns a replicaset.ReplicaSetFixture configured to be used as
@@ -222,16 +231,11 @@ class ShardedClusterFixture(interface.Fixture):
         mongos_logger = logging.loggers.new_logger(logger_name, parent=self.logger)
 
         mongos_options = copy.deepcopy(self.mongos_options)
-        configdb_hostname = socket.gethostname()
 
         if self.separate_configsvr:
-            configdb_replset = ShardedClusterFixture._CONFIGSVR_REPLSET_NAME
-            configdb_port = self.configsvr.port
-            mongos_options["configdb"] = "%s/%s:%d" % (configdb_replset,
-                                                       configdb_hostname,
-                                                       configdb_port)
+            mongos_options["configdb"] = self.configsvr.get_internal_connection_string()
         else:
-            mongos_options["configdb"] = "%s:%d" % (configdb_hostname, self.shards[0].port)
+            mongos_options["configdb"] = "%s:%d" % (socket.gethostname(), self.shards[0].port)
 
         return _MongoSFixture(mongos_logger,
                               self.job_num,
@@ -247,9 +251,9 @@ class ShardedClusterFixture(interface.Fixture):
         for more details.
         """
 
-        hostname = socket.gethostname()
-        self.logger.info("Adding %s:%d as a shard..." % (hostname, shard.port))
-        client.admin.command({"addShard": "%s:%d" % (hostname, shard.port)})
+        connection_string = shard.get_internal_connection_string()
+        self.logger.info("Adding %s as a shard...", connection_string)
+        client.admin.command({"addShard": connection_string})
 
 
 class _MongoSFixture(interface.Fixture):
@@ -351,3 +355,12 @@ class _MongoSFixture(interface.Fixture):
 
     def is_running(self):
         return self.mongos is not None and self.mongos.poll() is None
+
+    def get_internal_connection_string(self):
+        if self.mongos is None:
+            raise ValueError("Must call setup() before calling get_internal_connection_string()")
+
+        return "%s:%d" % (socket.gethostname(), self.port)
+
+    def get_driver_connection_url(self):
+        return "mongodb://" + self.get_internal_connection_string()
diff --git a/buildscripts/resmokelib/testing/fixtures/standalone.py b/buildscripts/resmokelib/testing/fixtures/standalone.py
index edb38177fa2..7e44aa2db72 100644
--- a/buildscripts/resmokelib/testing/fixtures/standalone.py
+++ b/buildscripts/resmokelib/testing/fixtures/standalone.py
@@ -178,8 +178,11 @@ class MongoDFixture(interface.Fixture):
     def is_running(self):
         return self.mongod is not None and self.mongod.poll() is None
 
-    def get_connection_string(self):
+    def get_internal_connection_string(self):
         if self.mongod is None:
-            raise ValueError("Must call setup() before calling get_connection_string()")
+            raise ValueError("Must call setup() before calling get_internal_connection_string()")
 
         return "%s:%d" % (socket.gethostname(), self.port)
+
+    def get_driver_connection_url(self):
+        return "mongodb://" + self.get_internal_connection_string()
diff --git a/buildscripts/resmokelib/testing/testcases.py b/buildscripts/resmokelib/testing/testcases.py
index de63c171088..0f6dfb8b447 100644
--- a/buildscripts/resmokelib/testing/testcases.py
+++ b/buildscripts/resmokelib/testing/testcases.py
@@ -173,7 +173,7 @@ class CPPIntegrationTestCase(TestCase):
     def configure(self, fixture):
         TestCase.configure(self, fixture)
 
-        self.program_options["connectionString"] = self.fixture.get_connection_string()
+        self.program_options["connectionString"] = self.fixture.get_internal_connection_string()
 
     def run_test(self):
         try:
@@ -279,6 +279,7 @@ class JSTestCase(TestCase):
                  js_filename,
                  shell_executable=None,
                  shell_options=None,
+                 use_connection_string=False,
                  test_kind="JSTest"):
         "Initializes the JSTestCase with the JS file to run."
 
@@ -289,6 +290,7 @@ class JSTestCase(TestCase):
 
         self.js_filename = js_filename
         self.shell_options = utils.default_if_none(shell_options, {}).copy()
+        self.use_connection_string = use_connection_string
 
     def configure(self, fixture):
         TestCase.configure(self, fixture)
@@ -349,10 +351,16 @@ class JSTestCase(TestCase):
             raise
 
     def _make_process(self):
-        return core.programs.mongo_shell_program(self.logger,
-                                                 executable=self.shell_executable,
-                                                 filename=self.js_filename,
-                                                 **self.shell_options)
+        connection_string = None
+        if self.use_connection_string:
+            connection_string = self.fixture.get_driver_connection_url()
+
+        return core.programs.mongo_shell_program(
+            self.logger,
+            executable=self.shell_executable,
+            filename=self.js_filename,
+            connection_string=connection_string,
+            **self.shell_options)
 
 
 class MongosTestCase(TestCase):
diff --git a/jstests/core/compact_keeps_indexes.js b/jstests/core/compact_keeps_indexes.js
index f2da7597cdf..d112dac3d61 100644
--- a/jstests/core/compact_keeps_indexes.js
+++ b/jstests/core/compact_keeps_indexes.js
@@ -1,6 +1,8 @@
 // SERVER-16676 Make sure compact doesn't leave the collection with bad indexes
 // SERVER-16967 Make sure compact doesn't crash while collections are being dropped
 // in a different database.
+//
+// @tags: [requires_parallel_shell]
 
 (function() {
     'use strict';
diff --git a/jstests/core/count10.js b/jstests/core/count10.js
index 2a1853c399a..453775c97f5 100644
--- a/jstests/core/count10.js
+++ b/jstests/core/count10.js
@@ -1,4 +1,11 @@
 // Test that interrupting a count returns an error code.
+//
+// @tags: [
+//   # This test attempts to perform a count command and find it using the currentOp command. The
+//   # former operation may be routed to a secondary in the replica set, whereas the latter must be
+//   # routed to the primary.
+//   assumes_read_preference_unchanged,
+// ]
 
 t = db.count10;
 t.drop();
diff --git a/jstests/core/count_plan_summary.js b/jstests/core/count_plan_summary.js
index 48891d21e8e..365f289c457 100644
--- a/jstests/core/count_plan_summary.js
+++ b/jstests/core/count_plan_summary.js
@@ -1,5 +1,11 @@
-// Test that the plan summary string appears in db.currentOp() for
-// count operations. SERVER-14064.
+// Test that the plan summary string appears in db.currentOp() for count operations. SERVER-14064.
+//
+// @tags: [
+//   # This test attempts to perform a find command and find it using the currentOp command. The
+//   # former operation may be routed to a secondary in the replica set, whereas the latter must be
+//   # routed to the primary.
+//   assumes_read_preference_unchanged,
+// ]
 
 var t = db.jstests_count_plan_summary;
 t.drop();
diff --git a/jstests/core/currentop.js b/jstests/core/currentop.js
index 296ad69355c..082554c9ec8 100644
--- a/jstests/core/currentop.js
+++ b/jstests/core/currentop.js
@@ -1,5 +1,7 @@
 /**
  * Tests that long-running operations show up in currentOp and report the locks they are holding.
+ *
+ * @tags: [requires_parallel_shell]
  */
 (function() {
     "use strict";
diff --git a/jstests/core/cursora.js b/jstests/core/cursora.js
index dfd9e28f281..ae281c2002f 100644
--- a/jstests/core/cursora.js
+++ b/jstests/core/cursora.js
@@ -1,3 +1,4 @@
+// @tags: [requires_parallel_shell]
 t = db.cursora;
 
 function run(n, atomic) {
diff --git a/jstests/core/distinct3.js b/jstests/core/distinct3.js
index 6ab21599f97..c36afcc37ec 100644
--- a/jstests/core/distinct3.js
+++ b/jstests/core/distinct3.js
@@ -1,4 +1,6 @@
 // Yield and delete test case for query optimizer cursor.  SERVER-4401
+//
+// @tags: [requires_parallel_shell]
 
 t = db.jstests_distinct3;
 t.drop();
diff --git a/jstests/core/explain3.js b/jstests/core/explain3.js
index 64db7686699..d2145bc1fb9 100644
--- a/jstests/core/explain3.js
+++ b/jstests/core/explain3.js
@@ -1,4 +1,8 @@
-/** SERVER-2451 Kill cursor while explain is yielding */
+/**
+ * SERVER-2451 Kill cursor while explain is yielding
+ *
+ * @tags: [requires_parallel_shell]
+ */
 
 t = db.jstests_explain3;
 t.drop();
diff --git a/jstests/core/find_and_modify_concurrent_update.js b/jstests/core/find_and_modify_concurrent_update.js
index 3986ac62ea9..fe52016623d 100644
--- a/jstests/core/find_and_modify_concurrent_update.js
+++ b/jstests/core/find_and_modify_concurrent_update.js
@@ -1,5 +1,7 @@
 // Ensures that find and modify will not apply an update to a document which, due to a concurrent
 // modification, no longer matches the query predicate.
+//
+// @tags: [requires_parallel_shell]
 (function() {
     "use strict";
 
diff --git a/jstests/core/geo_s2cursorlimitskip.js b/jstests/core/geo_s2cursorlimitskip.js
index 868b57de39f..9eb580edd25 100644
--- a/jstests/core/geo_s2cursorlimitskip.js
+++ b/jstests/core/geo_s2cursorlimitskip.js
@@ -1,4 +1,11 @@
 // Test various cursor behaviors
+//
+// @tags: [
+//   # This test attempts to enable profiling on a server and then get profiling data by reading
+//   # from the "system.profile" collection. The former operation must be routed to the primary in
+//   # a replica set, whereas the latter may be routed to a secondary.
+//   assumes_read_preference_unchanged,
+// ]
 var t = db.geo_s2getmmm;
 t.drop();
 t.ensureIndex({geo: "2dsphere"});
diff --git a/jstests/core/getlog2.js b/jstests/core/getlog2.js
index b6cf223b967..29b6d299123 100644
--- a/jstests/core/getlog2.js
+++ b/jstests/core/getlog2.js
@@ -1,4 +1,11 @@
 // tests getlog as well as slow querying logging
+//
+// @tags: [
+//   # This test attempts to perform a find command and see that it ran using the getLog command.
+//   # The former operation may be routed to a secondary in the replica set, whereas the latter must
+//   # be routed to the primary.
+//   assumes_read_preference_unchanged,
+// ]
 
 glcol = db.getLogTest2;
 glcol.drop();
diff --git a/jstests/core/index_filter_commands.js b/jstests/core/index_filter_commands.js
index 027731e97cf..641edf426a7 100644
--- a/jstests/core/index_filter_commands.js
+++ b/jstests/core/index_filter_commands.js
@@ -6,20 +6,24 @@
  *   Displays index filters for all query shapes in a collection.
  *
  * - planCacheClearFilters
- *   Clears index filter for a single query shape or,
- *   if the query shape is omitted, all filters for the collection.
+ *   Clears index filter for a single query shape or, if the query shape is omitted, all filters for
+ *   the collection.
  *
  * - planCacheSetFilter
  *   Sets index filter for a query shape. Overrides existing filter.
  *
- * Not a lot of data access in this test suite. Hint commands
- * manage a non-persistent mapping in the server of
- * query shape to list of index specs.
+ * Not a lot of data access in this test suite. Hint commands manage a non-persistent mapping in the
+ * server of query shape to list of index specs.
  *
- * Only time we might need to execute a query is to check the plan
- * cache state. We would do this with the planCacheListPlans command
- * on the same query shape with the index filters.
+ * Only time we might need to execute a query is to check the plan cache state. We would do this
+ * with the planCacheListPlans command on the same query shape with the index filters.
  *
+ * @tags: [
+ *   # This test attempts to perform queries with plan cache filters set up. The former operation
+ *   # may be routed to a secondary in the replica set, whereas the latter must be routed to the
+ *   # primary.
+ *   assumes_read_preference_unchanged,
+ * ]
  */
 
 var t = db.jstests_index_filter_commands;
diff --git a/jstests/core/index_stats.js b/jstests/core/index_stats.js
index 7db4559210c..508c8d25183 100644
--- a/jstests/core/index_stats.js
+++ b/jstests/core/index_stats.js
@@ -1,3 +1,10 @@
+// @tags: [
+//   # This test attempts to perform write operations and get index usage statistics using the
+//   # $indexStats stage. The former operation must be routed to the primary in a replica set,
+//   # whereas the latter may be routed to a secondary.
+//   assumes_read_preference_unchanged,
+// ]
+
 (function() {
     "use strict";
 
diff --git a/jstests/core/killop.js b/jstests/core/killop.js
index 66476ec10f4..4cbc5d54dde 100644
--- a/jstests/core/killop.js
+++ b/jstests/core/killop.js
@@ -10,6 +10,8 @@
  * terminate until the server determines that they've spent too much time in JS execution, typically
  * after 30 seconds of wall clock time have passed.  For these operations to take a long time, the
  * counted collection must not be empty; hence an initial write to the collection is required.
+ *
+ * @tags: [requires_parallel_shell]
  */
 
 t = db.jstests_killop;
@@ -73,4 +75,4 @@ jsTestLog("Waiting for ops to terminate");
 // don't want to pass if timeout killed the js function.
 var end = new Date();
 var diff = end - start;
-assert.lt(diff, 30000, "Start: " + start + "; end: " + end + "; diff: " + diff);
\ No newline at end of file
+assert.lt(diff, 30000, "Start: " + start + "; end: " + end + "; diff: " + diff);
diff --git a/jstests/core/killop_drop_collection.js b/jstests/core/killop_drop_collection.js
index 7138ee8eda6..c262d1b4ffd 100644
--- a/jstests/core/killop_drop_collection.js
+++ b/jstests/core/killop_drop_collection.js
@@ -3,6 +3,8 @@
  * to complete. Interrupting a collection drop could leave the database in an inconsistent state.
  * This test confirms that killOp won't interrupt a collection drop, and that the drop occurs
  * successfully.
+ *
+ * @tags: [requires_parallel_shell]
  */
 (function() {
     "use strict";
diff --git a/jstests/core/loadserverscripts.js b/jstests/core/loadserverscripts.js
index daf87b2475b..1c382d27ad4 100644
--- a/jstests/core/loadserverscripts.js
+++ b/jstests/core/loadserverscripts.js
@@ -1,5 +1,6 @@
-
 // Test db.loadServerScripts()
+//
+// @tags: [requires_parallel_shell]
 
 var testdb = db.getSisterDB("loadserverscripts");
 
diff --git a/jstests/core/max_time_ms.js b/jstests/core/max_time_ms.js
index 39fce0fc9ca..5147201cacc 100644
--- a/jstests/core/max_time_ms.js
+++ b/jstests/core/max_time_ms.js
@@ -1,4 +1,11 @@
 // Tests query/command option $maxTimeMS.
+//
+// @tags: [
+//   # This test attempts to perform read operations after having enabled the maxTimeAlwaysTimeOut
+//   # failpoint. The former operations may be routed to a secondary in the replica set, whereas the
+//   # latter must be routed to the primary.
+//   assumes_read_preference_unchanged,
+// ]
 
 var t = db.max_time_ms;
 var exceededTimeLimit = 50;  // ErrorCodes::ExceededTimeLimit
diff --git a/jstests/core/mr_killop.js b/jstests/core/mr_killop.js
index 186424b1db9..437a02511de 100644
--- a/jstests/core/mr_killop.js
+++ b/jstests/core/mr_killop.js
@@ -1,4 +1,6 @@
 // Test killop applied to m/r operations and child ops of m/r operations.
+//
+// @tags: [requires_parallel_shell]
 
 t = db.jstests_mr_killop;
 t.drop();
diff --git a/jstests/core/mr_optim.js b/jstests/core/mr_optim.js
index 7437753ca67..1c525ae3de3 100644
--- a/jstests/core/mr_optim.js
+++ b/jstests/core/mr_optim.js
@@ -3,8 +3,17 @@
 t = db.mr_optim;
 t.drop();
 
+// We drop the output collection to ensure the test can be run multiple times successfully. We
+// explicitly avoid using the DBCollection#drop() shell helper to avoid implicitly sharding the
+// collection during the sharded_collections_jscore_passthrough.yml test suite when reading the
+// results from the output collection in the reformat() function.
+var res = db.runCommand({drop: "mr_optim_out"});
+if (res.ok !== 1) {
+    assert.commandFailedWithCode(res, ErrorCodes.NamespaceNotFound);
+}
+
 for (var i = 0; i < 1000; ++i) {
-    t.save({a: Math.random(1000), b: Math.random(10000)});
+    assert.writeOK(t.save({a: Math.random(1000), b: Math.random(10000)}));
 }
 
 function m() {
@@ -21,7 +30,7 @@ function reformat(r) {
     if (r.results)
         cursor = r.results;
     else
-        cursor = r.find();
+        cursor = r.find().sort({_id: 1});
     cursor.forEach(function(z) {
         x[z._id] = z.value;
     });
@@ -43,4 +52,4 @@ res.drop();
 
 assert.eq(x, x2, "object from inline and collection are not equal");
 
-t.drop();
\ No newline at end of file
+t.drop();
diff --git a/jstests/core/notablescan.js b/jstests/core/notablescan.js
index 80306c08cf2..bb4c170a603 100644
--- a/jstests/core/notablescan.js
+++ b/jstests/core/notablescan.js
@@ -1,4 +1,11 @@
 // check notablescan mode
+//
+// @tags: [
+//   # This test attempts to perform read operations after having enabled the notablescan server
+//   # parameter. The former operations may be routed to a secondary in the replica set, whereas the
+//   # latter must be routed to the primary.
+//   assumes_read_preference_unchanged,
+// ]
 
 t = db.test_notablescan;
 t.drop();
diff --git a/jstests/core/plan_cache_clear.js b/jstests/core/plan_cache_clear.js
index 8f9cf0ea302..778239616b5 100644
--- a/jstests/core/plan_cache_clear.js
+++ b/jstests/core/plan_cache_clear.js
@@ -1,5 +1,12 @@
 // Test clearing of the plan cache, either manually through the planCacheClear command,
 // or due to system events such as an index build.
+//
+// @tags: [
+//   # This test attempts to perform queries and introspect/manipulate the server's plan cache
+//   # entries. The former operation may be routed to a secondary in the replica set, whereas the
+//   # latter must be routed to the primary.
+//   assumes_read_preference_unchanged,
+// ]
 
 var t = db.jstests_plan_cache_clear;
 t.drop();
diff --git a/jstests/core/plan_cache_list_plans.js b/jstests/core/plan_cache_list_plans.js
index b4be4ad46c4..14cf9c97c28 100644
--- a/jstests/core/plan_cache_list_plans.js
+++ b/jstests/core/plan_cache_list_plans.js
@@ -1,4 +1,11 @@
 // Test the planCacheListPlans command.
+//
+// @tags: [
+//   # This test attempts to perform queries and introspect the server's plan cache entries. The
+//   # former operation may be routed to a secondary in the replica set, whereas the latter must be
+//   # routed to the primary.
+//   assumes_read_preference_unchanged,
+// ]
 
 var t = db.jstests_plan_cache_list_plans;
 t.drop();
diff --git a/jstests/core/plan_cache_list_shapes.js b/jstests/core/plan_cache_list_shapes.js
index 4711940870d..f0061459968 100644
--- a/jstests/core/plan_cache_list_shapes.js
+++ b/jstests/core/plan_cache_list_shapes.js
@@ -1,5 +1,12 @@
 // Test the planCacheListQueryShapes command, which returns a list of query shapes
 // for the queries currently cached in the collection.
+//
+// @tags: [
+//   # This test attempts to perform queries with plan cache filters set up. The former operation
+//   # may be routed to a secondary in the replica set, whereas the latter must be routed to the
+//   # primary.
+//   assumes_read_preference_unchanged,
+// ]
 
 var t = db.jstests_plan_cache_list_shapes;
 t.drop();
diff --git a/jstests/core/plan_cache_shell_helpers.js b/jstests/core/plan_cache_shell_helpers.js
index a61421afc7b..f2ac0e7051f 100644
--- a/jstests/core/plan_cache_shell_helpers.js
+++ b/jstests/core/plan_cache_shell_helpers.js
@@ -1,4 +1,11 @@
 // Test the shell helpers which wrap the plan cache commands.
+//
+// @tags: [
+//   # This test attempts to perform queries and introspect the server's plan cache entries. The
+//   # former operation may be routed to a secondary in the replica set, whereas the latter must be
+//   # routed to the primary.
+//   assumes_read_preference_unchanged,
+// ]
 
 var t = db.jstests_plan_cache_shell_helpers;
 t.drop();
diff --git a/jstests/core/queryoptimizer3.js b/jstests/core/queryoptimizer3.js
index 4bc3754ff7a..b83a02cbf80 100644
--- a/jstests/core/queryoptimizer3.js
+++ b/jstests/core/queryoptimizer3.js
@@ -1,4 +1,6 @@
 // Check cases where index scans are aborted due to the collection being dropped.  SERVER-4400
+//
+// @tags: [requires_parallel_shell]
 
 t = db.jstests_queryoptimizer3;
 t.drop();
diff --git a/jstests/core/remove9.js b/jstests/core/remove9.js
index 9b7b2f31190..ed0c8f45130 100644
--- a/jstests/core/remove9.js
+++ b/jstests/core/remove9.js
@@ -1,4 +1,6 @@
 // SERVER-2009 Count odd numbered entries while updating and deleting even numbered entries.
+//
+// @tags: [requires_parallel_shell]
 
 t = db.jstests_remove9;
 t.drop();
diff --git a/jstests/core/removeb.js b/jstests/core/removeb.js
index 2141e138254..aba5976ccf7 100644
--- a/jstests/core/removeb.js
+++ b/jstests/core/removeb.js
@@ -1,4 +1,6 @@
 // Test removal of Records that have been reused since the remove operation began.  SERVER-5198
+//
+// @tags: [requires_parallel_shell]
 
 t = db.jstests_removeb;
 t.drop();
diff --git a/jstests/core/removec.js b/jstests/core/removec.js
index b4fe09ef970..15f62bc206d 100644
--- a/jstests/core/removec.js
+++ b/jstests/core/removec.js
@@ -1,4 +1,6 @@
 // Sanity test for removing documents with adjacent index keys.  SERVER-2008
+//
+// @tags: [requires_parallel_shell]
 
 t = db.jstests_removec;
 t.drop();
diff --git a/jstests/core/shellstartparallel.js b/jstests/core/shellstartparallel.js
index 7e288e0d589..f92c1d507dd 100644
--- a/jstests/core/shellstartparallel.js
+++ b/jstests/core/shellstartparallel.js
@@ -1,3 +1,4 @@
+// @tags: [requires_parallel_shell]
 function f() {
     throw Error("intentional_throw_to_test_assert_throws");
 }
diff --git a/jstests/core/startup_log.js b/jstests/core/startup_log.js
index 3b0cbe3464d..c73013d1744 100644
--- a/jstests/core/startup_log.js
+++ b/jstests/core/startup_log.js
@@ -1,101 +1,108 @@
-load('jstests/aggregation/extras/utils.js');

-

-(function() {

-    'use strict';

-

-    // Check that smallArray is entirely contained by largeArray

-    // returns false if a member of smallArray is not in largeArray

-    function arrayIsSubset(smallArray, largeArray) {

-        for (var i = 0; i < smallArray.length; i++) {

-            if (!Array.contains(largeArray, smallArray[i])) {

-                print("Could not find " + smallArray[i] + " in largeArray");

-                return false;

-            }

-        }

-

-        return true;

-    }

-

-    // Test startup_log

-    var stats = db.getSisterDB("local").startup_log.stats();

-    assert(stats.capped);

-

-    var latestStartUpLog =

-        db.getSisterDB("local").startup_log.find().sort({$natural: -1}).limit(1).next();

-    var serverStatus = db._adminCommand("serverStatus");

-    var cmdLine = db._adminCommand("getCmdLineOpts").parsed;

-

-    // Test that the startup log has the expected keys

-    var verbose = false;

-    var expectedKeys =

-        ["_id", "hostname", "startTime", "startTimeLocal", "cmdLine", "pid", "buildinfo"];

-    var keys = Object.keySet(latestStartUpLog);

-    assert(arrayEq(expectedKeys, keys, verbose), 'startup_log keys failed');

-

-    // Tests _id implicitly - should be comprised of host-timestamp

-    // Setup expected startTime and startTimeLocal from the supplied timestamp

-    var _id = latestStartUpLog._id.split('-');  // _id should consist of host-timestamp

-    var _idUptime = _id.pop();

-    var _idHost = _id.join('-');

-    var uptimeSinceEpochRounded = Math.floor(_idUptime / 1000) * 1000;

-    var startTime = new Date(uptimeSinceEpochRounded);  // Expected startTime

-

-    assert.eq(_idHost, latestStartUpLog.hostname, "Hostname doesn't match one from _id");

-    assert.eq(serverStatus.host.split(':')[0],

-              latestStartUpLog.hostname,

-              "Hostname doesn't match one in server status");

-    assert.closeWithinMS(startTime,

-                         latestStartUpLog.startTime,

-                         "StartTime doesn't match one from _id",

-                         2000);  // Expect less than 2 sec delta

-    assert.eq(cmdLine, latestStartUpLog.cmdLine, "cmdLine doesn't match that from getCmdLineOpts");

-    assert.eq(serverStatus.pid, latestStartUpLog.pid, "pid doesn't match that from serverStatus");

-

-    // Test buildinfo

-    var buildinfo = db.runCommand("buildinfo");

-    delete buildinfo.ok;  // Delete extra meta info not in startup_log

-    var isMaster = db._adminCommand("ismaster");

-

-    // Test buildinfo has the expected keys

-    var expectedKeys = [

-        "version",

-        "gitVersion",

-        "allocator",

-        "versionArray",

-        "javascriptEngine",

-        "openssl",

-        "buildEnvironment",

-        "debug",

-        "maxBsonObjectSize",

-        "bits",

-        "modules"

-    ];

-

-    var keys = Object.keySet(latestStartUpLog.buildinfo);

-    // Disabled to check

-    assert(arrayIsSubset(expectedKeys, keys),

-           "buildinfo keys failed! \n expected:\t" + expectedKeys + "\n actual:\t" + keys);

-    assert.eq(buildinfo,

-              latestStartUpLog.buildinfo,

-              "buildinfo doesn't match that from buildinfo command");

-

-    // Test version and version Array

-    var version = latestStartUpLog.buildinfo.version.split('-')[0];

-    var versionArray = latestStartUpLog.buildinfo.versionArray;

-    var versionArrayCleaned = versionArray.slice(0, 3);

-    if (versionArray[3] == -100) {

-        versionArrayCleaned[2] -= 1;

-    }

-

-    assert.eq(serverStatus.version,

-              latestStartUpLog.buildinfo.version,

-              "Mongo version doesn't match that from ServerStatus");

-    assert.eq(

-        version, versionArrayCleaned.join('.'), "version doesn't match that from the versionArray");

-    var jsEngine = latestStartUpLog.buildinfo.javascriptEngine;

-    assert((jsEngine == "none") || jsEngine.startsWith("mozjs"));

-    assert.eq(isMaster.maxBsonObjectSize,

-              latestStartUpLog.buildinfo.maxBsonObjectSize,

-              "maxBsonObjectSize doesn't match one from ismaster");

-

-})();

+/**
+ * This test attempts to read from the "local.startup_log" collection and assert that it has an
+ * entry matching the server's response from the "getCmdLineOpts" command. The former operation may
+ * be routed to a secondary in the replica set, whereas the latter must be routed to the primary.
+ *
+ * @tags: [assumes_read_preference_unchanged]
+ */
+load('jstests/aggregation/extras/utils.js');
+
+(function() {
+    'use strict';
+
+    // Check that smallArray is entirely contained by largeArray
+    // returns false if a member of smallArray is not in largeArray
+    function arrayIsSubset(smallArray, largeArray) {
+        for (var i = 0; i < smallArray.length; i++) {
+            if (!Array.contains(largeArray, smallArray[i])) {
+                print("Could not find " + smallArray[i] + " in largeArray");
+                return false;
+            }
+        }
+
+        return true;
+    }
+
+    // Test startup_log
+    var stats = db.getSisterDB("local").startup_log.stats();
+    assert(stats.capped);
+
+    var latestStartUpLog =
+        db.getSisterDB("local").startup_log.find().sort({$natural: -1}).limit(1).next();
+    var serverStatus = db._adminCommand("serverStatus");
+    var cmdLine = db._adminCommand("getCmdLineOpts").parsed;
+
+    // Test that the startup log has the expected keys
+    var verbose = false;
+    var expectedKeys =
+        ["_id", "hostname", "startTime", "startTimeLocal", "cmdLine", "pid", "buildinfo"];
+    var keys = Object.keySet(latestStartUpLog);
+    assert(arrayEq(expectedKeys, keys, verbose), 'startup_log keys failed');
+
+    // Tests _id implicitly - should be comprised of host-timestamp
+    // Setup expected startTime and startTimeLocal from the supplied timestamp
+    var _id = latestStartUpLog._id.split('-');  // _id should consist of host-timestamp
+    var _idUptime = _id.pop();
+    var _idHost = _id.join('-');
+    var uptimeSinceEpochRounded = Math.floor(_idUptime / 1000) * 1000;
+    var startTime = new Date(uptimeSinceEpochRounded);  // Expected startTime
+
+    assert.eq(_idHost, latestStartUpLog.hostname, "Hostname doesn't match one from _id");
+    assert.eq(serverStatus.host.split(':')[0],
+              latestStartUpLog.hostname,
+              "Hostname doesn't match one in server status");
+    assert.closeWithinMS(startTime,
+                         latestStartUpLog.startTime,
+                         "StartTime doesn't match one from _id",
+                         2000);  // Expect less than 2 sec delta
+    assert.eq(cmdLine, latestStartUpLog.cmdLine, "cmdLine doesn't match that from getCmdLineOpts");
+    assert.eq(serverStatus.pid, latestStartUpLog.pid, "pid doesn't match that from serverStatus");
+
+    // Test buildinfo
+    var buildinfo = db.runCommand("buildinfo");
+    delete buildinfo.ok;  // Delete extra meta info not in startup_log
+    var isMaster = db._adminCommand("ismaster");
+
+    // Test buildinfo has the expected keys
+    var expectedKeys = [
+        "version",
+        "gitVersion",
+        "allocator",
+        "versionArray",
+        "javascriptEngine",
+        "openssl",
+        "buildEnvironment",
+        "debug",
+        "maxBsonObjectSize",
+        "bits",
+        "modules"
+    ];
+
+    var keys = Object.keySet(latestStartUpLog.buildinfo);
+    // Disabled to check
+    assert(arrayIsSubset(expectedKeys, keys),
+           "buildinfo keys failed! \n expected:\t" + expectedKeys + "\n actual:\t" + keys);
+    assert.eq(buildinfo,
+              latestStartUpLog.buildinfo,
+              "buildinfo doesn't match that from buildinfo command");
+
+    // Test version and version Array
+    var version = latestStartUpLog.buildinfo.version.split('-')[0];
+    var versionArray = latestStartUpLog.buildinfo.versionArray;
+    var versionArrayCleaned = versionArray.slice(0, 3);
+    if (versionArray[3] == -100) {
+        versionArrayCleaned[2] -= 1;
+    }
+
+    assert.eq(serverStatus.version,
+              latestStartUpLog.buildinfo.version,
+              "Mongo version doesn't match that from ServerStatus");
+    assert.eq(
+        version, versionArrayCleaned.join('.'), "version doesn't match that from the versionArray");
+    var jsEngine = latestStartUpLog.buildinfo.javascriptEngine;
+    assert((jsEngine == "none") || jsEngine.startsWith("mozjs"));
+    assert.eq(isMaster.maxBsonObjectSize,
+              latestStartUpLog.buildinfo.maxBsonObjectSize,
+              "maxBsonObjectSize doesn't match one from ismaster");
+
+})();
diff --git a/jstests/core/top.js b/jstests/core/top.js
index 1aff2a4136b..a8f72091896 100644
--- a/jstests/core/top.js
+++ b/jstests/core/top.js
@@ -1,5 +1,11 @@
 /**
  * 1. check top numbers are correct
+ *
+ * This test attempts to perform read operations and get statistics using the top command. The
+ * former operation may be routed to a secondary in the replica set, whereas the latter must be
+ * routed to the primary.
+ *
+ * @tags: [assumes_read_preference_unchanged]
  */
 
 var name = "toptest";
diff --git a/jstests/core/updatef.js b/jstests/core/updatef.js
index 6bc8df4e0c1..925e718bbd9 100644
--- a/jstests/core/updatef.js
+++ b/jstests/core/updatef.js
@@ -1,4 +1,6 @@
 // Test unsafe management of nsdt on update command yield SERVER-3208
+//
+// @tags: [requires_parallel_shell]
 
 prefixNS = db.jstests_updatef;
 prefixNS.save({});
diff --git a/jstests/libs/override_methods/set_read_and_write_concerns.js b/jstests/libs/override_methods/set_read_and_write_concerns.js
index 30c853fb54b..267b5ab9bfc 100644
--- a/jstests/libs/override_methods/set_read_and_write_concerns.js
+++ b/jstests/libs/override_methods/set_read_and_write_concerns.js
@@ -57,6 +57,31 @@
         "updateUser",
     ]);
 
+    const kCommandsToEmulateWriteConcern = new Set([
+        "aggregate",
+        "appendOplogNote",
+        "captrunc",
+        "cleanupOrphaned",
+        "clone",
+        "cloneCollection",
+        "cloneCollectionAsCapped",
+        "convertToCapped",
+        "copydb",
+        "create",
+        "createIndexes",
+        "drop",
+        "dropDatabase",
+        "dropIndexes",
+        "emptycapped",
+        "godinsert",
+        "mapReduce",
+        "mapreduce",
+        "mapreduce.shardedfinish",
+        "moveChunk",
+        "renameCollection",
+        "revokePrivilegesFromRole",
+    ]);
+
     function runCommandWithReadAndWriteConcerns(
         conn, dbName, commandName, commandObj, func, makeFuncArgs) {
         if (typeof commandObj !== "object" || commandObj === null) {
@@ -79,10 +104,7 @@
 
         var shouldForceReadConcern = kCommandsSupportingReadConcern.has(commandName);
         var shouldForceWriteConcern = kCommandsSupportingWriteConcern.has(commandName);
-        var shouldEmulateWriteConcern =
-            (commandName === "aggregate" || commandName === "createIndexes" ||
-             commandName === "mapReduce" || commandName === "mapreduce" ||
-             commandName === "mapreduce.shardedfinish");
+        var shouldEmulateWriteConcern = kCommandsToEmulateWriteConcern.has(commandName);
 
         if (commandName === "aggregate") {
             if (OverrideHelpers.isAggregationWithOutStage(commandName, commandObjUnwrapped)) {
diff --git a/jstests/libs/override_methods/set_read_preference_secondary.js b/jstests/libs/override_methods/set_read_preference_secondary.js
new file mode 100644
index 00000000000..270bbf40272
--- /dev/null
+++ b/jstests/libs/override_methods/set_read_preference_secondary.js
@@ -0,0 +1,88 @@
+/**
+ * Use prototype overrides to set read preference to "secondary" when running tests.
+ */
+(function() {
+    "use strict";
+
+    load("jstests/libs/override_methods/override_helpers.js");
+
+    const kReadPreferenceSecondary = {
+        mode: "secondary"
+    };
+    const kCommandsSupportingReadPreference = new Set([
+        "aggregate",
+        "collStats",
+        "count",
+        "dbStats",
+        "distinct",
+        "find",
+        "geoNear",
+        "geoSearch",
+        "group",
+        "mapReduce",
+        "mapreduce",
+        "parallelCollectionScan",
+    ]);
+
+    function runCommandWithReadPreferenceSecondary(
+        conn, dbName, commandName, commandObj, func, makeFuncArgs) {
+        if (typeof commandObj !== "object" || commandObj === null) {
+            return func.apply(conn, makeFuncArgs(commandObj));
+        }
+
+        // If the command is in a wrapped form, then we look for the actual command object inside
+        // the query/$query object.
+        var commandObjUnwrapped = commandObj;
+        if (commandName === "query" || commandName === "$query") {
+            commandObjUnwrapped = commandObj[commandName];
+            commandName = Object.keys(commandObjUnwrapped)[0];
+        }
+
+        if (commandObj[commandName] === "system.profile") {
+            throw new Error("Cowardly refusing to run test with overridden read preference" +
+                            " when it reads from a non-replicated collection: " +
+                            tojson(commandObj));
+        }
+
+        var shouldForceReadPreference = kCommandsSupportingReadPreference.has(commandName);
+        if (OverrideHelpers.isAggregationWithOutStage(commandName, commandObjUnwrapped)) {
+            // An aggregation with a $out stage must be sent to the primary.
+            shouldForceReadPreference = false;
+        } else if ((commandName === "mapReduce" || commandName === "mapreduce") &&
+                   !OverrideHelpers.isMapReduceWithInlineOutput(commandName, commandObjUnwrapped)) {
+            // A map-reduce operation with non-inline output must be sent to the primary.
+            shouldForceReadPreference = false;
+        }
+
+        if (shouldForceReadPreference) {
+            if (commandObj === commandObjUnwrapped) {
+                // We wrap the command object using a "query" field rather than a "$query" field to
+                // match the implementation of DB.prototype._attachReadPreferenceToCommand().
+                commandObj = {
+                    query: commandObj
+                };
+            } else {
+                // We create a copy of 'commandObj' to avoid mutating the parameter the caller
+                // specified.
+                commandObj = Object.assign({}, commandObj);
+            }
+
+            if (commandObj.hasOwnProperty("$readPreference") &&
+                !bsonBinaryEqual({_: commandObj.$readPreference}, {_: kReadPreferenceSecondary})) {
+                throw new Error("Cowardly refusing to override read preference of command: " +
+                                tojson(commandObj));
+            }
+
+            commandObj.$readPreference = kReadPreferenceSecondary;
+        }
+
+        return func.apply(conn, makeFuncArgs(commandObj));
+    }
+
+    startParallelShell = () => {throw new Error(
+        "Cowardly refusing to a run a test that starts a parallel shell because prior to" +
+        " MongoDB 3.4 replica set connections couldn't be used in it.");
+    };
+
+    OverrideHelpers.overrideRunCommand(runCommandWithReadPreferenceSecondary);
+})();