add unit tests

tests/static/js/runtime-config.js

@@ -0,0 +1,40 @@
+import RuntimeConfig from '../../../static/js/runtime-config';
+
+describe('Runtime config data model functionality', () => {
+  it('Can set and get data', () => {
+    const runtimeConfig = new RuntimeConfig();
+    runtimeConfig.set('linkTarget', '_blank');
+    const linkTarget = runtimeConfig.get('linkTarget');
+    expect(linkTarget).toEqual('_blank');
+  });
+
+  it('The getAll function works', () => {
+    const runtimeConfig = new RuntimeConfig();
+    runtimeConfig.set('linkTarget', '_blank');
+    runtimeConfig.set('color', 'red');
+    const actualData = runtimeConfig.getAll();
+    const expectedData = {
+      linkTarget: '_blank',
+      color: 'red'
+    };
+    expect(actualData).toEqual(expectedData);
+  });
+
+  it('The _onUpdate callback is called when data is set', () => {
+    const runtimeConfig = new RuntimeConfig();
+    const mockCallback = jest.fn();
+    runtimeConfig._onUpdate(mockCallback);
+    runtimeConfig.set('linkTarget', '_blank');
+    expect(mockCallback).toHaveBeenCalled();
+  });
+
+  it('An error is thrown if the setter receives data which is not JSON serializable', () => {
+    const runtimeConfig = new RuntimeConfig();
+    const setNonSerializableData = () => {
+      const circularReference = {};
+      circularReference.myself = circularReference;
+      runtimeConfig.set('linkTarget', circularReference);
+    };
+    expect(setNonSerializableData).toThrowError();
+  });
+});