Adding graph nodes for all targets found to ensure that BUILD files a…

lang/java/src/main/java/com/google/devtools/build/bfg/JavaSourceFileParser.java

@@ -189,6 +189,7 @@ private static void parseFiles(
 
       boolean hasEdges = false;
       classToFile.put(qualifiedSrc, srcFilePath.toString());
+      classToClass.addNode(qualifiedSrc);
       for (QualifiedName qualifiedDst : parser.qualifiedTopLevelNames) {
         if (!qualifiedSrc.equals(qualifiedDst.value())) {
           classToClass.putEdge(qualifiedSrc, qualifiedDst.value());

lang/java/src/test/java/com/google/devtools/build/bfg/JavaSourceFileParserTest.java

@@ -172,6 +172,7 @@ public void createDepsGraph_unresolvedClasses() throws IOException {
 
     ImmutableGraph<String> actual = parser.getClassToClass();
     MutableGraph<String> expected = newGraph();
+    expected.addNode("Dummy");
 
     assertThatGraphsEqual(actual, expected);
     assertThat(parser.getUnresolvedClassNames()).containsExactly("Foo");
@@ -271,13 +272,14 @@ public void allFilesInSameDirAreOnACycle() throws IOException {
     ImmutableGraph<String> actual = parser.getClassToClass();
 
     MutableGraph<String> expected = newGraph();
+    expected.addNode("x.A");
     expected.putEdge("y.A", "y.B");
     expected.putEdge("y.B", "y.A");
     expected.putEdge("z.A", "z.B");
     expected.putEdge("z.B", "z.C");
     expected.putEdge("z.C", "z.A");
-    // Implicit: there's no tests.A and tests.B here, because 'tests/' is not in
-    // oneRulePerPackageRoots.
+    expected.addNode("tests.A");
+    expected.addNode("tests.B");
 
     assertThatGraphsEqual(actual, expected);
   }

src/main/java/com/google/devtools/build/bfg/Bfg.java

@@ -159,6 +159,7 @@ private ImmutableGraph<String> protoMultimapToGraph(
     MutableGraph<String> result = GraphBuilder.directed().build();
     m.forEach(
         (u, deps) -> {
+          result.addNode(u);
           for (String s : deps.getElementsList()) {
             result.putEdge(u, s);
           }