SERVER-6074 Add $slice aggregation expression

1 files changed, 81 insertions, 0 deletions

diff --git a/jstests/aggregation/bugs/server6074.js b/jstests/aggregation/bugs/server6074.js
new file mode 100644
index 00000000000..8adf6b7eca8
--- /dev/null
+++ b/jstests/aggregation/bugs/server6074.js
@@ -0,0 +1,81 @@
+// SERVER-6074: Add $slice aggregation expression.
+
+// For assertErrorCode.
+load('jstests/aggregation/extras/utils.js');
+
+(function() {
+    'use strict';
+
+    var coll = db.agg_slice_expr;
+    coll.drop();
+
+    // Need to have at least one document to ensure the pipeline executes.
+    assert.writeOK(coll.insert({}));
+
+    function testSlice(sliceArgs, expArray) {
+        var pipeline = [{$project: {_id: 0, slice: {$slice: sliceArgs}}}];
+        assert.eq(coll.aggregate(pipeline).toArray(), [{slice: expArray}]);
+    }
+
+    // Two argument form.
+
+    testSlice([[0, 1, 2, 3, 4], 2], [0, 1]);
+    testSlice([[0, 1, 2, 3, 4], 2.0], [0, 1]);
+    // Negative count
+    testSlice([[0, 1, 2, 3, 4], -2], [3, 4]);
+    testSlice([[0, 1, 2, 3, 4], -2.0], [3, 4]);
+    // Zero count.
+    testSlice([[0, 1, 2, 3, 4], 0], []);
+    // Out of bounds positive.
+    testSlice([[0, 1, 2, 3, 4], 10], [0, 1, 2, 3, 4]);
+    // Out of bounds negative.
+    testSlice([[0, 1, 2, 3, 4], -10], [0, 1, 2, 3, 4]);
+    // Null arguments
+    testSlice([null, -10], null);
+    testSlice([[0, 1, 2, 3, 4], null], null);
+
+    // Three argument form.
+
+    testSlice([[0, 1, 2, 3, 4], 1, 2], [1, 2]);
+    testSlice([[0, 1, 2, 3, 4], 1.0, 2.0], [1, 2]);
+    // Negative start index.
+    testSlice([[0, 1, 2, 3, 4], -3, 2], [2, 3]);
+    testSlice([[0, 1, 2, 3, 4], -5, 2], [0, 1]);
+    // Slice starts out of bounds.
+    testSlice([[0, 1, 2, 3, 4], -10, 2], [0, 1]);
+    testSlice([[0, 1, 2, 3, 4], 10, 2], []);
+    // Slice ends out of bounds.
+    testSlice([[0, 1, 2, 3, 4], 4, 3], [4]);
+    testSlice([[0, 1, 2, 3, 4], -1, 3], [4]);
+    // Null arguments
+    testSlice([[0, 1, 2, 3, 4], -1, null], null);
+
+    // Error cases.
+
+    // Wrong number of arguments.
+    assertErrorCode(coll, [{$project: {x: {$slice: [[1, 2, 3]]}}}], 28667);
+    assertErrorCode(coll, [{$project: {x: {$slice: [[1, 2, 3], 4, 5, 6]}}}], 28667);
+
+    // First argument is not an array.
+    assertErrorCode(coll, [{$project: {x: {$slice: ['one', 2]}}}], 28724);
+
+    // Second argument is not numeric.
+    assertErrorCode(coll, [{$project: {x: {$slice: [[1, 2], '2']}}}], 28725);
+
+    // Second argument is not integral.
+    assertErrorCode(coll, [{$project: {x: {$slice: [[1, 2], 1.5]}}}], 28726);
+    assertErrorCode(coll, [{$project: {x: {$slice: [[1, 2], Math.pow(2, 32)]}}}], 28726);
+    assertErrorCode(coll, [{$project: {x: {$slice: [[1, 2], -Math.pow(2, 31) - 1]}}}], 28726);
+
+    // Third argument is not numeric.
+    assertErrorCode(coll, [{$project: {x: {$slice: [[1, 2], 0, '2']}}}], 28727);
+
+    // Third argument is not integral.
+    assertErrorCode(coll, [{$project: {x: {$slice: [[1, 2], 0, 1.5]}}}], 28728);
+    assertErrorCode(coll, [{$project: {x: {$slice: [[1, 2], 0, Math.pow(2, 32)]}}}], 28728);
+    assertErrorCode(coll, [{$project: {x: {$slice: [[1, 2], 0, -Math.pow(2, 31) - 1]}}}], 28728);
+
+    // Third argument is not positive.
+    assertErrorCode(coll, [{$project: {x: {$slice: [[1, 2], 0, 0]}}}], 28729);
+    assertErrorCode(coll, [{$project: {x: {$slice: [[1, 2], 0, -1]}}}], 28729);
+}());