Add some tests

Only enough to mirror the few tests we have that exercise the existing
renderers. In the future, we should have a more comprehensive suite
that covers both html and md.

Author: jdkoren

test/model_test.dart

@@ -373,6 +373,7 @@ void main() {
           equals(utils.kTestPackagePublicLibraries - 5));
     });
 
+    // TODO consider moving these to a separate suite
     test('CategoryRendererHtml renders category label', () {
       Category category = packageGraph.publicPackages.first.categories.first;
       CategoryRendererHtml renderer = CategoryRendererHtml();
@@ -388,6 +389,21 @@ void main() {
       expect(renderer.renderLinkedName(category),
           '<a href="${HTMLBASE_PLACEHOLDER}topics/Superb-topic.html">Superb</a>');
     });
+
+    test('CategoryRendererMd renders category label', () {
+      Category category = packageGraph.publicPackages.first.categories.first;
+      CategoryRendererMd renderer = CategoryRendererMd();
+      expect(
+          renderer.renderCategoryLabel(category),
+          '[Superb](${HTMLBASE_PLACEHOLDER}topics/Superb-topic.html)');
+    });
+
+    test('CategoryRendererMd renders linkedName', () {
+      Category category = packageGraph.publicPackages.first.categories.first;
+      CategoryRendererMd renderer = CategoryRendererMd();
+      expect(renderer.renderLinkedName(category),
+          '[Superb](${HTMLBASE_PLACEHOLDER}topics/Superb-topic.html)');
+    });
   });
 
   group('LibraryContainer', () {

test/html/html_template_renderer_test.dart renamed to test/render/template_renderer_test.dart

@@ -23,4 +23,22 @@ void main() {
       expect(test, equals('<span class="deprecated">Banana</span> Fruit'));
     });
   });
+
+  group('MdTemplateRenderer', () {
+    MdTemplateRenderer renderer;
+
+    setUpAll(() {
+      renderer = MdTemplateRenderer();
+    });
+
+    test('composeLayoutTitle', () {
+      String test = renderer.composeLayoutTitle('Banana', 'Fruit', false);
+      expect(test, equals('Banana Fruit'));
+    });
+
+    test('composeLayoutTitle deprecated', () {
+      String test = renderer.composeLayoutTitle('Banana', 'Fruit', true);
+      expect(test, equals('~~Banana~~ Fruit'));
+    });
+  });
 }