test: add sampler test

Author: eldreygalindo

packages/opencensus-core/src/trace/sampler/sampler.ts

@@ -15,7 +15,7 @@
  */
 
 import {debug, randomSpanId} from '../../internal/util';
-import {Sampler} from './types'
+import {Sampler} from './types';
 
 const MIN_NUMBER = 1e-4;
 const MAX_NUMBER = 0xffffffffffffffff;
@@ -28,7 +28,7 @@ export class SamplerImpl {
   /**
    * Constructs a new SamplerImpl instance.
    * @param traceId Used for probability calculation
-  */
+   */
   constructor(traceId?: string) {
     if (traceId) {
       this.traceId = traceId;
@@ -63,10 +63,8 @@ export class SamplerImpl {
   probability(probability?: number): Sampler {
     if (probability == null || probability > MAX_NUMBER) {
       return this.always();
-    }
-    else if (probability < MIN_NUMBER) {
+    } else if (probability < MIN_NUMBER) {
       return this.never();
-
     }
     this.idUpperBound = probability * MAX_NUMBER;
     return this;
@@ -76,7 +74,7 @@ export class SamplerImpl {
    * Checks if trace belong the sample.
    * @param traceId Used to check the probability
    * @returns a boolean. True if the traceId is in probability
-   * False if the traceId is not in probability. 
+   * False if the traceId is not in probability.
    */
   shouldSample(traceId: string): boolean {
     const LOWER_BYTES = traceId.substring(16);
@@ -89,5 +87,4 @@ export class SamplerImpl {
       return false;
     }
   }
-
 }

packages/opencensus-core/test/test-sampler.ts

@@ -0,0 +1,106 @@
+/**
+ * Copyright 2018 Google Inc. All Rights Reserved.
+ *
+ * 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 * as assert from 'assert';
+import * as mocha from 'mocha';
+
+import {SamplerImpl} from '../src/trace/config/sampler';
+import {RootSpanImpl} from '../src/trace/model/rootspan';
+import {TracerImpl} from '../src/trace/model/tracer';
+
+const tracer = new TracerImpl();
+
+describe('Sampler', () => {
+  /**
+   * Should create a sampler
+   */
+  describe('new Sampler()', () => {
+    it('should create a Sampler instance', () => {
+      const sampler = new SamplerImpl();
+      assert.ok(sampler instanceof SamplerImpl);
+    });
+  });
+
+  /**
+   * Should create a sampler with traceId
+   */
+  describe('new Sampler(traceId)', () => {
+    it('should create a Sampler instance', () => {
+      const root = new RootSpanImpl(tracer);
+      const sampler = new SamplerImpl(root.traceId);
+      assert.ok(sampler instanceof SamplerImpl);
+    });
+  });
+
+  /**
+   * Should return the SamplerImpl
+   */
+  describe('always()', () => {
+    it('should return a sampler instance', () => {
+      const sampler = new SamplerImpl();
+      const samplerAlways = sampler.always();
+      assert.ok(samplerAlways instanceof SamplerImpl);
+    });
+  });
+
+  /**
+   * Should return the SamplerImpl
+   */
+  describe('never()', () => {
+    it('should return a sampler instance', () => {
+      const sampler = new SamplerImpl();
+      const samplerNever = sampler.never();
+      assert.ok(samplerNever instanceof SamplerImpl);
+    });
+  });
+
+  /**
+   * Should return the SamplerImpl
+   */
+  describe('probability()', () => {
+    it('should return a sampler instance', () => {
+      const PROBABILITY = 0.5;
+      const sampler = new SamplerImpl();
+      const samplerProbability = sampler.probability(PROBABILITY);
+      assert.ok(samplerProbability instanceof SamplerImpl);
+    });
+  });
+
+  /**
+   * Should return true
+   */
+  describe('shouldSample() always', () => {
+    it('should return true', () => {
+      const root = new RootSpanImpl(tracer);
+      const sampler = new SamplerImpl();
+      sampler.always();
+      const samplerShouldSampler = sampler.shouldSample(root.traceId);
+      assert.ok(samplerShouldSampler);
+    });
+  });
+  /**
+   * Should return false
+   */
+  describe('shouldSample() never', () => {
+    it('should return false', () => {
+      const root = new RootSpanImpl(tracer);
+      const sampler = new SamplerImpl();
+      sampler.never();
+      const samplerShouldSampler = sampler.shouldSample(root.traceId);
+      assert.ok(!samplerShouldSampler);
+    });
+  });
+});