diff --git a/views/ngXosViews/diagnostic/spec/logicTopologyHelper.test.js b/views/ngXosViews/diagnostic/spec/logicTopologyHelper.test.js
new file mode 100644
index 0000000..0353398
--- /dev/null
+++ b/views/ngXosViews/diagnostic/spec/logicTopologyHelper.test.js
@@ -0,0 +1,48 @@
+(function () {
+  'use strict';
+
+  describe('The Logic Topology Helper Service', () => {
+    
+    var Service;
+
+    beforeEach(module('xos.serviceTopology'));
+
+    // inject the rackHelper service
+    beforeEach(inject(function (_LogicTopologyHelper_) {
+      // The injector unwraps the underscores (_) from around the parameter names when matching
+      Service = _LogicTopologyHelper_;
+    }));
+
+    var customMatchers = {
+      toBeSimilar: () => {
+
+        const tolerance = 0.1;
+
+        return {
+          compare: (actual, expected) => {
+            return {
+              pass: (Math.abs(actual - expected) < tolerance),
+              message: `Expected ${actual} to be ${expected}`
+            }
+          }
+        }
+      }
+    };
+
+    beforeEach(function() {
+      jasmine.addMatchers(customMatchers);
+    });
+
+    it('should calculate horizontal position for each element', () => {
+      let [el0x, el1x, el2x, el3x, el4x, el5x] = Service.computeElementPosition(900);
+
+      expect(el0x).toBeSimilar(900 - 30);
+      expect(el1x).toBeSimilar(900 - 183.4);
+      expect(el2x).toBeSimilar(900 - 337.3);
+      expect(el3x).toBeSimilar(900 - 490.7);
+      expect(el4x).toBeSimilar(900 - 602.1);
+      expect(el5x).toBeSimilar(900 - 713.5);
+    });
+  });
+
+})();