1 files changed, 45 insertions, 37 deletions
diff --git a/jstests/core/ts1.js b/jstests/core/ts1.js
index 342ff3215d7..79a2db95dca 100644
--- a/jstests/core/ts1.js
+++ b/jstests/core/ts1.js
@@ -1,37 +1,45 @@
-t = db.ts1;
-t.drop();
-
-N = 20;
-
-for (i = 0; i < N; i++) {
-    t.insert({_id: i, x: new Timestamp()});
-    sleep(100);
-}
-
-function get(i) {
-    return t.findOne({_id: i}).x;
-}
-
-function cmp(a, b) {
-    if (a.t < b.t)
-        return -1;
-    if (a.t > b.t)
-        return 1;
-
-    return a.i - b.i;
-}
-
-for (i = 0; i < N - 1; i++) {
-    a = get(i);
-    b = get(i + 1);
-    // print( tojson(a) + "\t" + tojson(b) + "\t" + cmp(a,b) );
-    assert.gt(0, cmp(a, b), "cmp " + i);
-}
-
-assert.eq(N, t.find({x: {$type: 17}}).itcount(), "B1");
-assert.eq(0, t.find({x: {$type: 3}}).itcount(), "B2");
-
-t.insert({_id: 100, x: new Timestamp(123456, 50)});
-x = t.findOne({_id: 100}).x;
-assert.eq(123456, x.t, "C1");
-assert.eq(50, x.i, "C2");
+// Tests that timestamps are inserted in increasing order. This test assumes that timestamps
+// inserted within the same second will have increasing increment values, which may not be the case
+// if the inserts are into a sharded collection.
+// @tags: [assumes_unsharded_collection]
+(function() {
+    "use strict";
+    const t = db.ts1;
+    t.drop();
+
+    const N = 20;
+
+    for (let i = 0; i < N; i++) {
+        assert.writeOK(t.insert({_id: i, x: new Timestamp()}));
+        sleep(100);
+    }
+
+    function get(i) {
+        return t.findOne({_id: i}).x;
+    }
+
+    function cmp(a, b) {
+        if (a.t < b.t)
+            return -1;
+        if (a.t > b.t)
+            return 1;
+
+        return a.i - b.i;
+    }
+
+    for (let i = 0; i < N - 1; i++) {
+        const a = get(i);
+        const b = get(i + 1);
+        assert.gt(0,
+                  cmp(a, b),
+                  `Expected ${tojson(a)} to be smaller than ${tojson(b)} (at iteration ${i})`);
+    }
+
+    assert.eq(N, t.find({x: {$type: 17}}).itcount());
+    assert.eq(0, t.find({x: {$type: 3}}).itcount());
+
+    assert.writeOK(t.insert({_id: 100, x: new Timestamp(123456, 50)}));
+    const x = t.findOne({_id: 100}).x;
+    assert.eq(123456, x.t);
+    assert.eq(50, x.i);
+}());