Change when we check the sampler. (#657)

* Change when we check the sampler.

* Fix comments.

* Deprecate setIsSampled without an argument.

4 files changed, 38 insertions, 46 deletions

diff --git a/api/src/test/java/io/opencensus/trace/SpanContextTest.java b/api/src/test/java/io/opencensus/trace/SpanContextTest.java
index c211d513..f5a9954f 100644
--- a/api/src/test/java/io/opencensus/trace/SpanContextTest.java
+++ b/api/src/test/java/io/opencensus/trace/SpanContextTest.java
@@ -41,7 +41,7 @@ public class SpanContextTest {
       SpanContext.create(
           TraceId.fromBytes(secondTraceIdBytes),
           SpanId.fromBytes(secondSpanIdBytes),
-          TraceOptions.builder().setIsSampled().build());
+          TraceOptions.builder().setIsSampled(true).build());
 
   @Test
   public void invalidSpanContext() {
@@ -82,7 +82,8 @@ public class SpanContextTest {
   @Test
   public void getTraceOptions() {
     assertThat(first.getTraceOptions()).isEqualTo(TraceOptions.DEFAULT);
-    assertThat(second.getTraceOptions()).isEqualTo(TraceOptions.builder().setIsSampled().build());
+    assertThat(second.getTraceOptions())
+        .isEqualTo(TraceOptions.builder().setIsSampled(true).build());
   }
 
   @Test
@@ -93,13 +94,17 @@ public class SpanContextTest {
         SpanContext.create(
             TraceId.fromBytes(firstTraceIdBytes),
             SpanId.fromBytes(firstSpanIdBytes),
-            TraceOptions.DEFAULT));
+            TraceOptions.DEFAULT),
+        SpanContext.create(
+            TraceId.fromBytes(firstTraceIdBytes),
+            SpanId.fromBytes(firstSpanIdBytes),
+            TraceOptions.builder().setIsSampled(false).build()));
     tester.addEqualityGroup(
         second,
         SpanContext.create(
             TraceId.fromBytes(secondTraceIdBytes),
             SpanId.fromBytes(secondSpanIdBytes),
-            TraceOptions.builder().setIsSampled().build()));
+            TraceOptions.builder().setIsSampled(true).build()));
     tester.testEquals();
   }
 
@@ -111,6 +116,6 @@ public class SpanContextTest {
     assertThat(second.toString()).contains(TraceId.fromBytes(secondTraceIdBytes).toString());
     assertThat(second.toString()).contains(SpanId.fromBytes(secondSpanIdBytes).toString());
     assertThat(second.toString())
-        .contains(TraceOptions.builder().setIsSampled().build().toString());
+        .contains(TraceOptions.builder().setIsSampled(true).build().toString());
   }
 }
diff --git a/api/src/test/java/io/opencensus/trace/SpanTest.java b/api/src/test/java/io/opencensus/trace/SpanTest.java
index 60c58b6a..1e05e60f 100644
--- a/api/src/test/java/io/opencensus/trace/SpanTest.java
+++ b/api/src/test/java/io/opencensus/trace/SpanTest.java
@@ -46,7 +46,7 @@ public class SpanTest {
         SpanContext.create(
             TraceId.generateRandomId(random),
             SpanId.generateRandomId(random),
-            TraceOptions.builder().setIsSampled().build());
+            TraceOptions.builder().setIsSampled(true).build());
     notSampledSpanContext =
         SpanContext.create(
             TraceId.generateRandomId(random),
diff --git a/api/src/test/java/io/opencensus/trace/TraceOptionsTest.java b/api/src/test/java/io/opencensus/trace/TraceOptionsTest.java
index 7d0019b0..a892384b 100644
--- a/api/src/test/java/io/opencensus/trace/TraceOptionsTest.java
+++ b/api/src/test/java/io/opencensus/trace/TraceOptionsTest.java
@@ -33,7 +33,10 @@ public class TraceOptionsTest {
   @Test
   public void getOptions() {
     assertThat(TraceOptions.DEFAULT.getOptions()).isEqualTo(0);
-    assertThat(TraceOptions.builder().setIsSampled().build().getOptions()).isEqualTo(1);
+    assertThat(TraceOptions.builder().setIsSampled(false).build().getOptions()).isEqualTo(0);
+    assertThat(TraceOptions.builder().setIsSampled(true).build().getOptions()).isEqualTo(1);
+    assertThat(TraceOptions.builder().setIsSampled(true).setIsSampled(false).build().getOptions())
+        .isEqualTo(0);
     assertThat(TraceOptions.fromBytes(firstBytes).getOptions()).isEqualTo(-1);
     assertThat(TraceOptions.fromBytes(secondBytes).getOptions()).isEqualTo(1);
     assertThat(TraceOptions.fromBytes(thirdBytes).getOptions()).isEqualTo(6);
@@ -42,7 +45,7 @@ public class TraceOptionsTest {
   @Test
   public void isSampled() {
     assertThat(TraceOptions.DEFAULT.isSampled()).isFalse();
-    assertThat(TraceOptions.builder().setIsSampled().build().isSampled()).isTrue();
+    assertThat(TraceOptions.builder().setIsSampled(true).build().isSampled()).isTrue();
   }
 
   @Test
@@ -56,7 +59,7 @@ public class TraceOptionsTest {
   public void builder_FromOptions() {
     assertThat(
             TraceOptions.builder(TraceOptions.fromBytes(thirdBytes))
-                .setIsSampled()
+                .setIsSampled(true)
                 .build()
                 .getOptions())
         .isEqualTo(6 | 1);
@@ -67,7 +70,7 @@ public class TraceOptionsTest {
     EqualsTester tester = new EqualsTester();
     tester.addEqualityGroup(TraceOptions.DEFAULT);
     tester.addEqualityGroup(
-        TraceOptions.fromBytes(secondBytes), TraceOptions.builder().setIsSampled().build());
+        TraceOptions.fromBytes(secondBytes), TraceOptions.builder().setIsSampled(true).build());
     tester.addEqualityGroup(TraceOptions.fromBytes(firstBytes));
     tester.testEquals();
   }
@@ -75,6 +78,7 @@ public class TraceOptionsTest {
   @Test
   public void traceOptions_ToString() {
     assertThat(TraceOptions.DEFAULT.toString()).contains("sampled=false");
-    assertThat(TraceOptions.builder().setIsSampled().build().toString()).contains("sampled=true");
+    assertThat(TraceOptions.builder().setIsSampled(true).build().toString())
+        .contains("sampled=true");
   }
 }
diff --git a/api/src/test/java/io/opencensus/trace/samplers/SamplersTest.java b/api/src/test/java/io/opencensus/trace/samplers/SamplersTest.java
index a9e79cc6..0999e8f8 100644
--- a/api/src/test/java/io/opencensus/trace/samplers/SamplersTest.java
+++ b/api/src/test/java/io/opencensus/trace/samplers/SamplersTest.java
@@ -33,12 +33,14 @@ import org.junit.runners.JUnit4;
 /** Unit tests for {@link Samplers}. */
 @RunWith(JUnit4.class)
 public class SamplersTest {
+  private static final String SPAN_NAME = "MySpanName";
+  private static final int NUM_SAMPLE_TRIES = 1000;
   private final Random random = new Random(1234);
   private final TraceId traceId = TraceId.generateRandomId(random);
   private final SpanId parentSpanId = SpanId.generateRandomId(random);
   private final SpanId spanId = SpanId.generateRandomId(random);
   private final SpanContext sampledSpanContext =
-      SpanContext.create(traceId, parentSpanId, TraceOptions.builder().setIsSampled().build());
+      SpanContext.create(traceId, parentSpanId, TraceOptions.builder().setIsSampled(true).build());
   private final SpanContext notSampledSpanContext =
       SpanContext.create(traceId, parentSpanId, TraceOptions.DEFAULT);
 
@@ -114,59 +116,40 @@ public class SamplersTest {
     Samplers.probabilitySampler(-0.00001);
   }
 
-  private final void probabilitySampler_AlwaysReturnTrueForSampled(Sampler sampler) {
-    final int numSamples = 100; // Number of traces for which to generate sampling decisions.
-    for (int i = 0; i < numSamples; i++) {
-      assertThat(
-              sampler.shouldSample(
-                  sampledSpanContext,
-                  false,
-                  TraceId.generateRandomId(random),
-                  spanId,
-                  "bar",
-                  Collections.<Span>emptyList()))
-          .isTrue();
-    }
-  }
-
-  private final void probabilitySampler_SamplesWithProbabilityForUnsampled(
-      Sampler sampler, double probability) {
-    final int numSamples = 1000; // Number of traces for which to generate sampling decisions.
+  // Applies the given sampler to NUM_SAMPLE_TRIES random traceId/spanId pairs.
+  private static void assertSamplerSamplesWithProbability(
+      Sampler sampler, SpanContext parent, double probability) {
+    Random random = new Random(1234);
     int count = 0; // Count of spans with sampling enabled
-    for (int i = 0; i < numSamples; i++) {
+    for (int i = 0; i < NUM_SAMPLE_TRIES; i++) {
       if (sampler.shouldSample(
-          notSampledSpanContext,
+          parent,
           false,
           TraceId.generateRandomId(random),
-          spanId,
-          "bar",
+          SpanId.generateRandomId(random),
+          SPAN_NAME,
           Collections.<Span>emptyList())) {
         count++;
       }
     }
-    double proportionSampled = (double) count / numSamples;
+    double proportionSampled = (double) count / NUM_SAMPLE_TRIES;
     // Allow for a large amount of slop (+/- 10%) in number of sampled traces, to avoid flakiness.
     assertThat(proportionSampled < probability + 0.1 && proportionSampled > probability - 0.1)
         .isTrue();
   }
 
   @Test
-  public void probabilitySamper_SamplesWithProbability() {
+  public void probabilitySampler_differentProbabilities() {
     final Sampler neverSample = Samplers.probabilitySampler(0.0);
-    probabilitySampler_AlwaysReturnTrueForSampled(neverSample);
-    probabilitySampler_SamplesWithProbabilityForUnsampled(neverSample, 0.0);
+    assertSamplerSamplesWithProbability(neverSample, sampledSpanContext, 0.0);
     final Sampler alwaysSample = Samplers.probabilitySampler(1.0);
-    probabilitySampler_AlwaysReturnTrueForSampled(alwaysSample);
-    probabilitySampler_SamplesWithProbabilityForUnsampled(alwaysSample, 1.0);
+    assertSamplerSamplesWithProbability(alwaysSample, sampledSpanContext, 1.0);
     final Sampler fiftyPercentSample = Samplers.probabilitySampler(0.5);
-    probabilitySampler_AlwaysReturnTrueForSampled(fiftyPercentSample);
-    probabilitySampler_SamplesWithProbabilityForUnsampled(fiftyPercentSample, 0.5);
+    assertSamplerSamplesWithProbability(fiftyPercentSample, sampledSpanContext, 0.5);
     final Sampler twentyPercentSample = Samplers.probabilitySampler(0.2);
-    probabilitySampler_AlwaysReturnTrueForSampled(twentyPercentSample);
-    probabilitySampler_SamplesWithProbabilityForUnsampled(twentyPercentSample, 0.2);
+    assertSamplerSamplesWithProbability(twentyPercentSample, sampledSpanContext, 0.2);
     final Sampler twoThirdsSample = Samplers.probabilitySampler(2.0 / 3.0);
-    probabilitySampler_AlwaysReturnTrueForSampled(twoThirdsSample);
-    probabilitySampler_SamplesWithProbabilityForUnsampled(twoThirdsSample, 2.0 / 3.0);
+    assertSamplerSamplesWithProbability(twoThirdsSample, sampledSpanContext, 2.0 / 3.0);
   }
 
   @Test