ThreadLocalScopeManager implements ScopeManager { @Override public Span activeSpan() { ThreadLocalScope scope = tlsScope.get(); return scope == null ? null : scope.span(); }  @Override Scope activate(Span span); @Override Span activeSpan();  }
@Test public void missingActiveSpan() throws Exception { Span missingSpan = source.activeSpan(); assertNull(missingSpan); }