SERVER-31477 Add $trim, $ltrim and $rtrim expressions.

1 files changed, 99 insertions, 0 deletions

diff --git a/jstests/aggregation/expressions/trim.js b/jstests/aggregation/expressions/trim.js
new file mode 100644
index 00000000000..34d8573f259
--- /dev/null
+++ b/jstests/aggregation/expressions/trim.js
@@ -0,0 +1,99 @@
+/**
+ * Basic tests for the $trim, $ltrim, and $rtrim expressions.
+ */
+(function() {
+    "use strict";
+    load("jstests/aggregation/extras/utils.js");  // For assertErrorCode, testExpression and
+                                                  // testExpressionWithCollation.
+
+    const coll = db.trim_expressions;
+
+    testExpression(coll, {$trim: {input: " abc "}}, "abc");
+    testExpression(coll, {$trim: {input: " a b\nc "}}, "a b\nc");
+    testExpression(coll, {$ltrim: {input: "\t abc "}}, "abc ");
+    testExpression(coll, {$rtrim: {input: "\t abc "}}, "\t abc");
+    testExpression(
+        coll,
+        {$map: {input: {$split: ["4, 5, 6, 7,8,9, 10", ","]}, in : {$trim: {input: "$$this"}}}},
+        ["4", "5", "6", "7", "8", "9", "10"]);
+
+    // Test that the trim expressions do not respect the collation.
+    const caseInsensitive = {locale: "en_US", strength: 2};
+    testExpressionWithCollation(coll, {$trim: {input: "xXx", chars: "x"}}, "X", caseInsensitive);
+    testExpressionWithCollation(coll, {$rtrim: {input: "xXx", chars: "x"}}, "xX", caseInsensitive);
+    testExpressionWithCollation(coll, {$ltrim: {input: "xXx", chars: "x"}}, "Xx", caseInsensitive);
+
+    // Test using inputs from documents.
+    coll.drop();
+    assert.writeOK(coll.insert([
+        {_id: 0, name: ", Charlie"},
+        {_id: 1, name: "Obama\t,  Barack"},
+        {_id: 2, name: " Ride,  Sally   "}
+    ]));
+
+    assert.eq(
+        coll.aggregate([
+                {$sort: {_id: 1}},
+                {
+                  $project: {
+                      firstName: {$trim: {input: {$arrayElemAt: [{$split: ["$name", ","]}, 1]}}}
+                  }
+                }
+            ])
+            .toArray(),
+        [
+          {_id: 0, firstName: "Charlie"},
+          {_id: 1, firstName: "Barack"},
+          {_id: 2, firstName: "Sally"}
+        ]);
+
+    coll.drop();
+    assert.writeOK(coll.insert([
+        {_id: 0, poorlyParsedWebTitle: "The title of my document"},
+        {_id: 1, poorlyParsedWebTitle: "\u2001\u2002 Odd unicode indentation"},
+        {_id: 2, poorlyParsedWebTitle: "\u2001\u2002 Odd unicode indentation\u200A"},
+    ]));
+    assert.eq(coll.aggregate([
+                      {$sort: {_id: 1}},
+                      {$project: {title: {$ltrim: {input: "$poorlyParsedWebTitle"}}}}
+                  ])
+                  .toArray(),
+              [
+                {_id: 0, title: "The title of my document"},
+                {_id: 1, title: "Odd unicode indentation"},
+                {_id: 2, title: "Odd unicode indentation\u200A"}
+              ]);
+
+    coll.drop();
+    assert.writeOK(coll.insert([
+        {_id: 0, proof: "Left as an exercise for the reader∎"},
+        {_id: 1, proof: "∎∃ proof∎"},
+        {
+          _id: 2,
+          proof: "Just view the problem as a continuous DAG whose elements are taylor series∎"
+        },
+        {_id: 3, proof: null},
+        {_id: 4},
+    ]));
+    assert.eq(
+        coll.aggregate(
+                [{$sort: {_id: 1}}, {$project: {proof: {$rtrim: {input: "$proof", chars: "∎"}}}}])
+            .toArray(),
+        [
+          {_id: 0, proof: "Left as an exercise for the reader"},
+          {_id: 1, proof: "∎∃ proof"},
+          {
+            _id: 2,
+            proof: "Just view the problem as a continuous DAG whose elements are taylor series"
+          },
+          {_id: 3, proof: null},
+          {_id: 4, proof: null},
+        ]);
+
+    // Test that errors are reported correctly.
+    assertErrorCode(coll, [{$project: {x: {$trim: " x "}}}], 50696);
+    assertErrorCode(coll, [{$project: {x: {$trim: {input: 4}}}}], 50699);
+    assertErrorCode(coll, [{$project: {x: {$trim: {input: {$add: [4, 2]}}}}}], 50699);
+    assertErrorCode(coll, [{$project: {x: {$trim: {input: "$_id"}}}}], 50699);
+    assertErrorCode(coll, [{$project: {x: {$trim: {input: " x ", chars: "$_id"}}}}], 50700);
+}());