diff --git a/toolkit/devtools/server/tests/unit/test_blackboxing-04.js b/toolkit/devtools/server/tests/unit/test_blackboxing-04.js
index fce7ce983469..0cc0b550f67b 100644
--- a/toolkit/devtools/server/tests/unit/test_blackboxing-04.js
+++ b/toolkit/devtools/server/tests/unit/test_blackboxing-04.js
@@ -53,7 +53,7 @@ function test_black_box()
     "" + function runTest() { // line 1
       doStuff(                // line 2
         function (n) {        // line 3
-          n;                  // line 4
+          return n;           // line 4
         }                     // line 5
       );                      // line 6
     }                         // line 7
diff --git a/toolkit/devtools/server/tests/unit/test_blackboxing-05.js b/toolkit/devtools/server/tests/unit/test_blackboxing-05.js
index c69710709805..15aac2726245 100644
--- a/toolkit/devtools/server/tests/unit/test_blackboxing-05.js
+++ b/toolkit/devtools/server/tests/unit/test_blackboxing-05.js
@@ -47,15 +47,15 @@ function test_black_box()
   );
 
   Components.utils.evalInSandbox(
-    "" + function runTest() { // line 1
-      doStuff(                // line 2
-        function (n) {        // line 3
-          debugger;           // line 4
-        }                     // line 5
-      );                      // line 6
-    }                         // line 7
-    + "\ndebugger;\n"         // line 8
-    + "runTest()",            // line 9
+    "" + function runTest() {                   // line 1
+      doStuff(                                  // line 2
+        function (n) {                          // line 3
+          debugger;                             // line 4
+        }                                       // line 5
+      );                                        // line 6
+    }                                           // line 7
+    + "\ndebugger;\n"                           // line 8
+    + "try { runTest() } catch (ex) { }",       // line 9
     gDebuggee,
     "1.8",
     SOURCE_URL,
diff --git a/toolkit/devtools/server/tests/unit/test_stepping-06.js b/toolkit/devtools/server/tests/unit/test_stepping-06.js
index d92f831cbe75..3dcb99fd4fb4 100644
--- a/toolkit/devtools/server/tests/unit/test_stepping-06.js
+++ b/toolkit/devtools/server/tests/unit/test_stepping-06.js
@@ -71,20 +71,20 @@ function test_simple_stepping()
   });
 
   gDebuggee.eval("var line0 = Error().lineNumber;\n" +
-                 "function f() {\n" + // line0 + 1
-                 "  debugger;\n" +    // line0 + 2
-                 "  var a = 10;\n" +  // line0 + 3
-                 "  return a;\n" +    // line0 + 4
-                 "}\n" +              // line0 + 5
-                 "function g() {\n" + // line0 + 6
-                 "  debugger;\n" +    // line0 + 7
-                 "}\n" +              // line0 + 8
-                 "function h() {\n" + // line0 + 9
-                 "  debugger;\n" +    // line0 + 10
-                 "  throw 'ah';\n" +  // line0 + 11
-                 "  return 2;\n" +    // line0 + 12
-                 "}\n" +              // line0 + 13
-                 "f();\n" +           // line0 + 14
-                 "g();\n" +           // line0 + 15
-                 "h();\n");           // line0 + 16
+                 "function f() {\n" +                   // line0 + 1
+                 "  debugger;\n" +                      // line0 + 2
+                 "  var a = 10;\n" +                    // line0 + 3
+                 "  return a;\n" +                      // line0 + 4
+                 "}\n" +                                // line0 + 5
+                 "function g() {\n" +                   // line0 + 6
+                 "  debugger;\n" +                      // line0 + 7
+                 "}\n" +                                // line0 + 8
+                 "function h() {\n" +                   // line0 + 9
+                 "  debugger;\n" +                      // line0 + 10
+                 "  throw 'ah';\n" +                    // line0 + 11
+                 "  return 2;\n" +                      // line0 + 12
+                 "}\n" +                                // line0 + 13
+                 "f();\n" +                             // line0 + 14
+                 "g();\n" +                             // line0 + 15
+                 "try { h() } catch (ex) { };\n");      // line0 + 16
 }