diff -r 000000000000 -r 6474c204b198 toolkit/devtools/server/tests/unit/test_breakpoint-18.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolkit/devtools/server/tests/unit/test_breakpoint-18.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,73 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * Check that we only break on offsets that are entry points for the line we are
+ * breaking on. Bug 907278.
+ */
+
+var gDebuggee;
+var gClient;
+var gThreadClient;
+
+function run_test()
+{
+  initTestDebuggerServer();
+  gDebuggee = addTestGlobal("test-breakpoints");
+  gDebuggee.console = { log: x => void x };
+  gClient = new DebuggerClient(DebuggerServer.connectPipe());
+  gClient.connect(function () {
+    attachTestTabAndResume(gClient,
+                           "test-breakpoints",
+                           function (aResponse, aTabClient, aThreadClient) {
+      gThreadClient = aThreadClient;
+      setUpCode();
+    });
+  });
+  do_test_pending();
+}
+
+const URL = "test.js";
+
+function setUpCode() {
+  gClient.addOneTimeListener("newSource", setBreakpoint);
+  Cu.evalInSandbox(
+    "" + function test() {
+      console.log("foo bar");
+      debugger;
+    },
+    gDebuggee,
+    "1.8",
+    URL
+  );
+}
+
+function setBreakpoint() {
+  gClient.addOneTimeListener("resumed", runCode);
+  gThreadClient.setBreakpoint({
+    url: URL,
+    line: 1
+  }, ({ error }) => {
+    do_check_true(!error);
+  });
+}
+
+function runCode() {
+  gClient.addOneTimeListener("paused", testBPHit);
+  gDebuggee.test();
+}
+
+function testBPHit(event, { why }) {
+  do_check_eq(why.type, "breakpoint");
+  gClient.addOneTimeListener("paused", testDbgStatement);
+  gThreadClient.resume();
+}
+
+function testDbgStatement(event, { why }) {
+  // Should continue to the debugger statement.
+  do_check_eq(why.type, "debuggerStatement");
+  // Not break on another offset from the same line (that isn't an entry point
+  // to the line)
+  do_check_neq(why.type, "breakpoint");
+  finishClient(gClient);
+}