Add a setStatus method in the Span. (#779)

* Add a setStatus method in the Span.

* Update after feedback.

* Run ./gradlew goJF

* Update comment in EndSpanOptions.

2 files changed, 9 insertions, 7 deletions

diff --git a/api/src/test/java/io/opencensus/trace/BlankSpanTest.java b/api/src/test/java/io/opencensus/trace/BlankSpanTest.java
index 4e8342e2..b9760c2f 100644
--- a/api/src/test/java/io/opencensus/trace/BlankSpanTest.java
+++ b/api/src/test/java/io/opencensus/trace/BlankSpanTest.java
@@ -55,6 +55,7 @@ public class BlankSpanTest {
     BlankSpan.INSTANCE.addNetworkEvent(NetworkEvent.builder(NetworkEvent.Type.SENT, 1L).build());
     BlankSpan.INSTANCE.addLink(
         Link.fromSpanContext(SpanContext.INVALID, Link.Type.CHILD_LINKED_SPAN));
+    BlankSpan.INSTANCE.setStatus(Status.OK);
     BlankSpan.INSTANCE.end(EndSpanOptions.DEFAULT);
     BlankSpan.INSTANCE.end();
   }
diff --git a/api/src/test/java/io/opencensus/trace/EndSpanOptionsTest.java b/api/src/test/java/io/opencensus/trace/EndSpanOptionsTest.java
index cae21064..b6ab8e0e 100644
--- a/api/src/test/java/io/opencensus/trace/EndSpanOptionsTest.java
+++ b/api/src/test/java/io/opencensus/trace/EndSpanOptionsTest.java
@@ -26,19 +26,20 @@ import org.junit.runners.JUnit4;
 /** Unit tests for {@link EndSpanOptions}. */
 @RunWith(JUnit4.class)
 public class EndSpanOptionsTest {
-  @Test(expected = NullPointerException.class)
-  public void setNullStatus() {
-    EndSpanOptions.builder().setStatus(null).build();
-  }
-
   @Test
   public void endSpanOptions_DefaultOptions() {
-    assertThat(EndSpanOptions.DEFAULT.getStatus()).isEqualTo(Status.OK);
+    assertThat(EndSpanOptions.DEFAULT.getStatus()).isNull();
     assertThat(EndSpanOptions.DEFAULT.getSampleToLocalSpanStore()).isFalse();
   }
 
   @Test
-  public void setStatus() {
+  public void setStatus_Ok() {
+    EndSpanOptions endSpanOptions = EndSpanOptions.builder().setStatus(Status.OK).build();
+    assertThat(endSpanOptions.getStatus()).isEqualTo(Status.OK);
+  }
+
+  @Test
+  public void setStatus_Error() {
     EndSpanOptions endSpanOptions =
         EndSpanOptions.builder()
             .setStatus(Status.CANCELLED.withDescription("ThisIsAnError"))