SERVER-63826: Add test discovery interface to resmoke

7 files changed, 190 insertions, 2 deletions

diff --git a/buildscripts/resmokelib/discovery/__init__.py b/buildscripts/resmokelib/discovery/__init__.py
new file mode 100644
index 00000000000..2a01c49d0ed
--- /dev/null
+++ b/buildscripts/resmokelib/discovery/__init__.py
@@ -0,0 +1,142 @@
+"""Subcommands for test discovery."""
+from typing import List, Optional
+
+import yaml
+from pydantic import BaseModel
+
+import buildscripts.resmokelib.parser as _parser
+from buildscripts.resmokelib import suitesconfig
+from buildscripts.resmokelib.plugin import PluginInterface, Subcommand
+from buildscripts.resmokelib.testing.suite import Suite
+
+TEST_DISCOVERY_SUBCOMMAND = "test-discovery"
+SUITECONFIG_SUBCOMMAND = "suiteconfig"
+MULTIVERSION_SUBCOMMAND = "multiversion-config"
+
+
+class SuiteTestList(BaseModel):
+    """Collection of tests belonging to a suite."""
+
+    suite_name: str
+    tests: List[str]
+
+
+class TestDiscoverySubcommand(Subcommand):
+    """Subcommand for test discovery."""
+
+    def __init__(self, suite_name: str) -> None:
+        """
+        Initialize the subcommand.
+
+        :param suite_name: Suite to discover.
+        """
+        _parser.set_run_options()
+        self.suite_name = suite_name
+        self.suite_config = suitesconfig
+
+    def execute(self):
+        """Execute the subcommand."""
+        suite = self.suite_config.get_suite(self.suite_name)
+        test_list = self.gather_tests(suite)
+
+        print(yaml.safe_dump(test_list.dict()))
+
+    @staticmethod
+    def gather_tests(suite: Suite) -> SuiteTestList:
+        """
+        Find all the tests that belong to the given suite.
+
+        :param suite: Suite to query.
+        :return: List of tests belonging to the suite.
+        """
+        test_list = []
+        for tests in suite.tests:
+            # `tests` could return individual tests or lists of tests, we need to handle both.
+            if isinstance(tests, list):
+                test_list.extend(tests)
+            else:
+                test_list.append(tests)
+
+        return SuiteTestList(
+            suite_name=suite.get_display_name(),
+            tests=test_list,
+        )
+
+
+class SuiteConfigSubcommand(Subcommand):
+    """Subcommand for discovering configuration of a suite."""
+
+    def __init__(self, suite_name: str) -> None:
+        """
+        Initialize the subcommand.
+
+        :param suite_name: Suite to discover.
+        """
+        _parser.set_run_options()
+        self.suite_name = suite_name
+        self.suite_config = suitesconfig
+
+    def execute(self):
+        """Execute the subcommand."""
+        suite = self.suite_config.get_suite(self.suite_name)
+        print(yaml.safe_dump(suite.get_config()))
+
+
+class MultiversionConfig(BaseModel):
+    """Multiversion Configuration."""
+
+    last_versions: List[str]
+
+
+class MultiversionConfigSubcommand(Subcommand):
+    """Subcommand for discovering multiversion configuration."""
+
+    def execute(self):
+        """Execute the subcommand."""
+        mv_config = self.determine_multiversion_config()
+        print(yaml.safe_dump(mv_config.dict()))
+
+    @staticmethod
+    def determine_multiversion_config() -> MultiversionConfig:
+        """Discover the current multiversion configuration."""
+        from buildscripts.resmokelib import multiversionconstants
+        return MultiversionConfig(last_versions=multiversionconstants.OLD_VERSIONS)
+
+
+class DiscoveryPlugin(PluginInterface):
+    """Test discovery plugin."""
+
+    def add_subcommand(self, subparsers) -> None:
+        """
+        Add parser options for this plugin.
+
+        :param subparsers: argparse subparsers
+        """
+        parser = subparsers.add_parser(TEST_DISCOVERY_SUBCOMMAND,
+                                       help="Discover what tests are run by a suite.")
+        parser.add_argument("--suite", metavar="SUITE", help="Suite to run against.")
+
+        parser = subparsers.add_parser(SUITECONFIG_SUBCOMMAND,
+                                       help="Display configuration of a test suite.")
+        parser.add_argument("--suite", metavar="SUITE", help="Suite to run against.")
+
+        parser = subparsers.add_parser(MULTIVERSION_SUBCOMMAND,
+                                       help="Display configuration for multiversion testing")
+
+    def parse(self, subcommand, parser, parsed_args, **kwargs) -> Optional[Subcommand]:
+        """
+        Resolve command-line options to a Subcommand or None.
+
+        :param subcommand: equivalent to parsed_args.command.
+        :param parser: parser used.
+        :param parsed_args: output of parsing.
+        :param kwargs: additional args.
+        :return: None or a Subcommand.
+        """
+        if subcommand == TEST_DISCOVERY_SUBCOMMAND:
+            return TestDiscoverySubcommand(parsed_args.suite)
+        if subcommand == SUITECONFIG_SUBCOMMAND:
+            return SuiteConfigSubcommand(parsed_args.suite)
+        if subcommand == MULTIVERSION_SUBCOMMAND:
+            return MultiversionConfigSubcommand()
+        return None
diff --git a/buildscripts/resmokelib/multiversionconstants.py b/buildscripts/resmokelib/multiversionconstants.py
index a25b9bdc2ae..6055e771c24 100644
--- a/buildscripts/resmokelib/multiversionconstants.py
+++ b/buildscripts/resmokelib/multiversionconstants.py
@@ -172,3 +172,7 @@ REQUIRES_FCV_TAG = ",".join([tag_str(fcv) for fcv in fcv_constants.requires_fcv_
 # Generate evergreen project names for all FCVs less than latest.
 EVERGREEN_PROJECTS = ['mongodb-mongo-master']
 EVERGREEN_PROJECTS.extend([evg_project_str(fcv) for fcv in fcv_constants.fcvs_less_than_latest])
+
+OLD_VERSIONS = ["last_lts"]
+if LAST_LTS_FCV != LAST_CONTINUOUS_FCV:
+    OLD_VERSIONS.append("last_continuous")
diff --git a/buildscripts/resmokelib/parser.py b/buildscripts/resmokelib/parser.py
index 70ec736ab95..d247d854b70 100644
--- a/buildscripts/resmokelib/parser.py
+++ b/buildscripts/resmokelib/parser.py
@@ -4,7 +4,9 @@ import argparse
 import shlex
 
 from buildscripts.resmokelib import configure_resmoke
-from buildscripts.resmokelib.generate_fcv_constants import GenerateFCVConstantsPlugin
+from buildscripts.resmokelib.discovery import DiscoveryPlugin
+from buildscripts.resmokelib.generate_fcv_constants import \
+    GenerateFCVConstantsPlugin
 from buildscripts.resmokelib.hang_analyzer import HangAnalyzerPlugin
 from buildscripts.resmokelib.powercycle import PowercyclePlugin
 from buildscripts.resmokelib.run import RunPlugin
@@ -18,6 +20,7 @@ _PLUGINS = [
     PowercyclePlugin(),
     SymbolizerPlugin(),
     GenerateFCVConstantsPlugin(),
+    DiscoveryPlugin(),
 ]
 
 
diff --git a/buildscripts/resmokelib/plugin.py b/buildscripts/resmokelib/plugin.py
index 3ce8f788d62..75a3ff9f317 100644
--- a/buildscripts/resmokelib/plugin.py
+++ b/buildscripts/resmokelib/plugin.py
@@ -8,7 +8,7 @@ class Subcommand(object):
 
     def execute(self):
         """Execute the subcommand."""
-        raise NotImplementedError("execue must be implemented by Subcommand subclasses")
+        raise NotImplementedError("execute must be implemented by Subcommand subclasses")
 
 
 class PluginInterface(abc.ABC):
diff --git a/buildscripts/resmokelib/testing/suite.py b/buildscripts/resmokelib/testing/suite.py
index 5de8bdd5855..7d7b87c08dd 100644
--- a/buildscripts/resmokelib/testing/suite.py
+++ b/buildscripts/resmokelib/testing/suite.py
@@ -87,6 +87,10 @@ class Suite(object):  # pylint: disable=too-many-instance-attributes
         # report intermediate results.
         self._partial_reports = None
 
+    def get_config(self):
+        """Return the configuration of this suite."""
+        return self._suite_config
+
     def __repr__(self):
         """Create a string representation of object for debugging."""
         return f"{self.test_kind}:{self._suite_name}"
diff --git a/buildscripts/tests/resmokelib/discovery/__init__.py b/buildscripts/tests/resmokelib/discovery/__init__.py
new file mode 100644
index 00000000000..4b7a2bb941b
--- /dev/null
+++ b/buildscripts/tests/resmokelib/discovery/__init__.py
@@ -0,0 +1 @@
+"""Empty."""
diff --git a/buildscripts/tests/resmokelib/discovery/test_discovery.py b/buildscripts/tests/resmokelib/discovery/test_discovery.py
new file mode 100644
index 00000000000..e3a45e03e63
--- /dev/null
+++ b/buildscripts/tests/resmokelib/discovery/test_discovery.py
@@ -0,0 +1,34 @@
+"""Unit tests for discovery subcommand."""
+
+import unittest
+from unittest.mock import MagicMock
+
+import buildscripts.resmokelib.discovery as under_test
+from buildscripts.resmokelib.testing.suite import Suite
+
+# pylint: disable=missing-docstring
+
+
+class TestTestDiscoverySubCommand(unittest.TestCase):
+    def test_gather_tests_should_return_discovered_tests(self):
+        suite_name = "my suite"
+        mock_suite = MagicMock(spec_set=Suite)
+        mock_suite.get_display_name.return_value = suite_name
+        mock_suite.tests = [
+            "test_0.js",
+            "test_1.js",
+            [
+                "test_2.js",
+                "test_3.js",
+                "test_4.js",
+            ],
+            "test_5.js",
+        ]
+        test_discovery_subcommand = under_test.TestDiscoverySubcommand(suite_name)
+
+        tests = test_discovery_subcommand.gather_tests(mock_suite)
+
+        self.assertEqual(suite_name, tests.suite_name)
+
+        for i in range(6):
+            self.assertIn(f"test_{i}.js", tests.tests)