diff --git a/tests/mocha/connection_db_test.js b/tests/mocha/connection_db_test.js
index 091503721..d05c7ba98 100644
--- a/tests/mocha/connection_db_test.js
+++ b/tests/mocha/connection_db_test.js
@@ -199,14 +199,10 @@ suite('Connection Database', function() {
     setup(function() {
       // Ignore type checks.
       sinon.stub(this.database.connectionChecker_, 'doTypeChecks')
-          .callsFake(function(_a, _b) {
-            return true;
-          });
+          .returns(true);
       // Ignore safety checks.
       sinon.stub(this.database.connectionChecker_, 'doSafetyChecks')
-          .callsFake(function(_a, _b) {
-            return Blockly.Connection.CAN_CONNECT;
-          });
+          .returns(Blockly.Connection.CAN_CONNECT);
       // Skip everything but the distance checks.
       sinon.stub(this.database.connectionChecker_, 'doDragChecks')
           .callsFake(function(a, b, distance) {
diff --git a/tests/mocha/event_test.js b/tests/mocha/event_test.js
index b1be8f7d0..5b3dc34b0 100644
--- a/tests/mocha/event_test.js
+++ b/tests/mocha/event_test.js
@@ -730,7 +730,7 @@ suite('Events', function() {
       // The first varCreate and move event should have been ignored.
       sinon.assert.callCount(this.changeListenerSpy, 3);
       // Expect two events on undo stack: varCreate and block create.
-      chai.assert.equal(2, this.workspace.undoStack_.length,
+      chai.assert.equal(this.workspace.undoStack_.length, 2,
           'Undo stack length');
 
       assertNthCallEventArgEquals(
diff --git a/tests/mocha/navigation_test.js b/tests/mocha/navigation_test.js
index ba2b5a9c7..555520340 100644
--- a/tests/mocha/navigation_test.js
+++ b/tests/mocha/navigation_test.js
@@ -395,9 +395,7 @@ suite('Navigation', function() {
       var block = this.workspace.getTopBlocks()[0];
       var field = block.inputList[0].fieldRow[0];
 
-      sinon.stub(field, 'onBlocklyAction').callsFake(function(){
-        return true;
-      });
+      sinon.stub(field, 'onBlocklyAction').returns(true);
       this.workspace.getCursor().setCurNode(Blockly.ASTNode.createFieldNode(field));
 
       var isHandled = Blockly.navigation.onBlocklyAction(Blockly.navigation.ACTION_OUT);