[core/api] added tests for FeatureFlags.tsx

packages/core/src/api/app/FeatureFlags.test.tsx

@@ -0,0 +1,155 @@
+/*
+ * Copyright 2020 Spotify AB
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import React, { useContext } from 'react';
+import { render } from '@testing-library/react';
+import {
+  FeatureFlags,
+  FeatureFlagsContext,
+  FeatureFlagsContextProvider,
+} from './FeatureFlags';
+import { FeatureFlagState } from '../apis/definitions/featureFlags';
+
+describe('FeatureFlags', () => {
+  beforeEach(() => {
+    window.localStorage.clear();
+  });
+
+  describe('#get', () => {
+    it('defaults to .NotEnabled', () => {
+      expect(FeatureFlags.get('enable-feature-flag')).toBe(
+        FeatureFlagState.NotEnabled,
+      );
+    });
+
+    it('returns a .Enabled state', () => {
+      FeatureFlags.set('enable-feature-flag', FeatureFlagState.Enabled);
+      expect(FeatureFlags.get('enable-feature-flag')).toBe(
+        FeatureFlagState.Enabled,
+      );
+    });
+
+    it('returns a .NotEnabled state', () => {
+      FeatureFlags.set('enable-feature-flag', FeatureFlagState.NotEnabled);
+      expect(FeatureFlags.get('enable-feature-flag')).toBe(
+        FeatureFlagState.NotEnabled,
+      );
+    });
+  });
+
+  describe('#set', () => {
+    it('fails if name is less than three characters', () => {
+      expect(() => {
+        FeatureFlags.set('ab', FeatureFlagState.NotEnabled);
+      }).toThrow(/minimum length of three characters/i);
+    });
+
+    it('fails if name is greater than 150 characters', () => {
+      expect(() => {
+        FeatureFlags.set(
+          'loremipsumdolorsitametconsecteturadipiscingelitnuncvitaeportaexaullamcorperturpismaurisutmattisnequemorbisediaculisauguevivamuspulvinarcursuseratblandithendreritquisqueuttinciduntmagnavestibulumblanditaugueat',
+          FeatureFlagState.NotEnabled,
+        );
+      }).toThrow(/not exceed 150 characters/i);
+    });
+
+    it('fails if name does not start with a lowercase letter', () => {
+      expect(() => {
+        FeatureFlags.set('123456789', FeatureFlagState.NotEnabled);
+      }).toThrow(/start with a lowercase letter/i);
+    });
+
+    it('fails if name contains characters other than lowercase letters, numbers and hyphens', () => {
+      expect(() => {
+        FeatureFlags.set('Invalid_Feature_Flag', FeatureFlagState.NotEnabled);
+      }).toThrow(/only contain lowercase letters, numbers and hyphens/i);
+    });
+
+    it('fails if state is not recognized from FeatureFlagState', () => {
+      expect(() => {
+        // @ts-ignore
+        FeatureFlags.set('valid-feature-flag', 'invalid state');
+      }).toThrow(/requires a recognized value from the FeatureFlagState/i);
+    });
+
+    it('sets a feature flag to enabled', () => {
+      expect(window.localStorage.featureFlags).toBeUndefined();
+      FeatureFlags.set('valid-feature-flag', FeatureFlagState.Enabled);
+      expect(window.localStorage.featureFlags).toBe(
+        '{"valid-feature-flag":true}',
+      );
+    });
+
+    it('sets a feature flag to disabled', () => {
+      expect(window.localStorage.featureFlags).toBeUndefined();
+      FeatureFlags.set('valid-feature-flag', FeatureFlagState.NotEnabled);
+      expect(window.localStorage.featureFlags).toBe('{}');
+    });
+
+    it('sets a feature flag to disabled then enabled', () => {
+      expect(window.localStorage.featureFlags).toBeUndefined();
+      FeatureFlags.set('valid-feature-flag', FeatureFlagState.NotEnabled);
+      FeatureFlags.set('valid-feature-flag', FeatureFlagState.Enabled);
+      expect(window.localStorage.featureFlags).toBe(
+        '{"valid-feature-flag":true}',
+      );
+    });
+
+    it('sets multiple feature flags', () => {
+      expect(window.localStorage.featureFlags).toBeUndefined();
+      FeatureFlags.set('valid-feature-flag', FeatureFlagState.Enabled);
+      FeatureFlags.set('another-valid-feature-flag', FeatureFlagState.Enabled);
+      expect(window.localStorage.featureFlags).toBe(
+        '{"valid-feature-flag":true,"another-valid-feature-flag":true}',
+      );
+    });
+  });
+});
+
+describe('FeatureFlagsContext', () => {
+  it('returns an empty list without the context', () => {
+    expect.assertions(1);
+
+    const Component = () => {
+      const { registeredFeatureFlags } = useContext(FeatureFlagsContext);
+      expect(registeredFeatureFlags).toEqual([]);
+      return null;
+    };
+
+    render(<Component />);
+  });
+
+  it('returns a list of registered feature flags', () => {
+    expect.assertions(1);
+
+    const mockFeatureFlags = [
+      { name: 'feature-flag-one', pluginId: 'plugin-one' },
+      { name: 'feature-flag-two', pluginId: 'plugin-two' },
+    ];
+
+    const Component = () => {
+      const { registeredFeatureFlags } = useContext(FeatureFlagsContext);
+      expect(registeredFeatureFlags).toBe(mockFeatureFlags);
+      return null;
+    };
+
+    render(
+      <FeatureFlagsContextProvider registeredFeatureFlags={mockFeatureFlags}>
+        <Component />
+      </FeatureFlagsContextProvider>,
+    );
+  });
+});

packages/core/src/api/app/FeatureFlags.tsx

@@ -56,8 +56,34 @@ class FeatureFlagsImpl implements FeatureFlagsApi {
   set(name: FeatureFlagName, state: FeatureFlagState): void {
     const flags = this.getUserEnabledFeatureFlags();
 
-    if (state === FeatureFlagState.NotEnabled) flags.delete(name);
-    if (state === FeatureFlagState.Enabled) flags.add(name);
+    if (name.length < 3) {
+      throw new Error(
+        'The `name` argument must have a minimum length of three characters.',
+      );
+    }
+
+    if (name.length > 150) {
+      throw new Error('The `name` argument must not exceed 150 characters.');
+    }
+
+    if (!name.match(/^[a-z]+[a-z0-9-]+$/)) {
+      throw new Error(
+        'The `name` argument must start with a lowercase letter and only contain lowercase letters, numbers and hyphens.' +
+          'Examples: feature-flag-one, alpha, release-2020',
+      );
+    }
+
+    if (state === FeatureFlagState.Enabled) {
+      flags.add(name);
+    } else if (state === FeatureFlagState.NotEnabled) {
+      flags.delete(name);
+    } else {
+      throw new Error(
+        'The `state` argument requires a recognized value from the FeatureFlagState enum. ' +
+          'Please check the Backstage documentation to see all the available options.' +
+          'Example values: FeatureFlagState.NotEnabled, FeatureFlagState.Enabled',
+      );
+    }
 
     window.localStorage.setItem(
       this.localStorageKey,