1 files changed, 57 insertions, 0 deletions
diff --git a/dom/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_02.js b/dom/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_02.js
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index 000000000..680ac9b58
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+++ b/dom/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_02.js
@@ -0,0 +1,57 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// HeapSnapshot.prototype.takeCensus behaves plausibly as we allocate objects.
+//
+// Exact object counts vary in ways we can't predict. For example,
+// BaselineScripts can hold onto "template objects", which exist only to hold
+// the shape and type for newly created objects. When BaselineScripts are
+// discarded, these template objects go with them.
+//
+// So instead of expecting precise counts, we expect counts that are at least as
+// many as we would expect given the object graph we've built.
+//
+// Ported from js/src/jit-tests/debug/Memory-takeCensus-02.js
+
+function run_test() {
+  // A Debugger with no debuggees had better not find anything.
+  var dbg = new Debugger;
+  var census0 = saveHeapSnapshotAndTakeCensus(dbg);
+  Census.walkCensus(census0, "census0", Census.assertAllZeros);
+
+  function newGlobalWithDefs() {
+    var g = newGlobal();
+    g.eval(`
+           function times(n, fn) {
+             var a=[];
+             for (var i = 0; i<n; i++)
+               a.push(fn());
+             return a;
+           }
+           `);
+    return g;
+  }
+
+  // Allocate a large number of various types of objects, and check that census
+  // finds them.
+  var g = newGlobalWithDefs();
+  dbg.addDebuggee(g);
+
+  g.eval("var objs = times(100, () => ({}));");
+  g.eval("var rxs  = times(200, () => /foo/);");
+  g.eval("var ars  = times(400, () => []);");
+  g.eval("var fns  = times(800, () => () => {});");
+
+  var census1 = dbg.memory.takeCensus(dbg);
+  Census.walkCensus(census1, "census1",
+                    Census.assertAllNotLessThan(
+                      { "objects":
+                        { "Object":   { count: 100 },
+                          "RegExp":   { count: 200 },
+                          "Array":    { count: 400 },
+                          "Function": { count: 800 }
+                        }
+                      }));
+
+  do_test_finished();
+}