Only send monitor update on change

test/unit/engine_runtime.js

@@ -10,3 +10,49 @@ test('spec', t => {
 
     t.end();
 });
+
+test('monitorWouldChange_false', t => {
+    const r = new Runtime();
+    const currentMonitorState = {
+        id: 'xklj4#!',
+        category: 'data',
+        label: 'turtle whereabouts',
+        value: '25',
+        x: 0,
+        y: 0
+    };
+    const newMonitorDelta = {
+        id: 'xklj4#!',
+        value: String(25)
+    };
+    t.equals(false, r._monitorWouldChange(currentMonitorState, newMonitorDelta));
+    t.end();
+});
+
+test('monitorWouldChange_true', t => {
+    const r = new Runtime();
+    const currentMonitorState = {
+        id: 'xklj4#!',
+        category: 'data',
+        label: 'turtle whereabouts',
+        value: '25',
+        x: 0,
+        y: 0
+    };
+
+    // Value change
+    let newMonitorDelta = {
+        id: 'xklj4#!',
+        value: String(24)
+    };
+    t.equal(true, r._monitorWouldChange(currentMonitorState, newMonitorDelta));
+
+    // Prop change
+    newMonitorDelta = {
+        id: 'xklj4#!',
+        moose: 7
+    };
+    t.equal(true, r._monitorWouldChange(currentMonitorState, newMonitorDelta));
+
+    t.end();
+});