Add support for testing boolean expressions

Author: amorimjuliana

src/plug.ts

@@ -280,6 +280,11 @@ export class GlobalPlug implements Plug {
         return this.sdk.evaluate(expression, options);
     }
 
+    public test(expression: string, options: EvaluationOptions = {}): Promise<boolean> {
+        return this.evaluate(expression, options)
+            .then(result => result === true);
+    }
+
     public async unplug(): Promise<void> {
         if (this.instance === undefined) {
             return;

test/plug.test.ts

@@ -602,6 +602,63 @@ describe('The Croct plug', () => {
         expect(() => croct.evaluate('foo', {timeout: 5})).toThrow('Croct is not plugged in.');
     });
 
+    test('should allow to test expressions', async () => {
+        const config: SdkFacadeConfiguration = {appId: APP_ID};
+        const sdkFacade = SdkFacade.init(config);
+
+        const initialize = jest.spyOn(SdkFacade, 'init').mockReturnValue(sdkFacade);
+
+        croct.plug(config);
+
+        expect(initialize).toBeCalledWith(config);
+
+        const evaluate = jest.spyOn(sdkFacade, 'evaluate').mockResolvedValue(true);
+
+        const promise = croct.test('user\'s name is "Carol"', {timeout: 5});
+
+        await expect(promise).resolves.toBe(true);
+
+        expect(evaluate).toBeCalledWith('user\'s name is "Carol"', {timeout: 5});
+    });
+
+    test('should test expressions assuming non-boolean results as false', async () => {
+        const config: SdkFacadeConfiguration = {appId: APP_ID};
+        const sdkFacade = SdkFacade.init(config);
+
+        const initialize = jest.spyOn(SdkFacade, 'init').mockReturnValue(sdkFacade);
+
+        croct.plug(config);
+
+        expect(initialize).toBeCalledWith(config);
+
+        const evaluate = jest.spyOn(sdkFacade, 'evaluate').mockResolvedValue('foo');
+
+        const promise = croct.test('user\'s name is "Carol"', {timeout: 5});
+
+        await expect(promise).resolves.toBe(false);
+
+        expect(evaluate).toBeCalledWith('user\'s name is "Carol"', {timeout: 5});
+    });
+
+    test('should not test expressions assuming errors as false', async () => {
+        const config: SdkFacadeConfiguration = {appId: APP_ID};
+        const sdkFacade = SdkFacade.init(config);
+
+        const initialize = jest.spyOn(SdkFacade, 'init').mockReturnValue(sdkFacade);
+
+        croct.plug(config);
+
+        expect(initialize).toBeCalledWith(config);
+
+        const evaluate = jest.spyOn(sdkFacade, 'evaluate').mockRejectedValue(undefined);
+
+        const promise = croct.test('user\'s name is "Carol"', {timeout: 5});
+
+        await expect(promise).rejects.toBeUndefined();
+
+        expect(evaluate).toBeCalledWith('user\'s name is "Carol"', {timeout: 5});
+    });
+
     test('should wait for the plugins to disable before closing the SDK', async () => {
         let unloadFooPlugin: () => void = jest.fn();
         const fooDisable = jest.fn().mockImplementation(() => new Promise<void>(resolve => {