Remove mentions of ScrollableViewport from flutter_markdown (#8132)

Also, actually run the flutter_markdown tests.
diff --git a/dev/bots/test.dart b/dev/bots/test.dart
index 43b1d87..ca445f1 100644
--- a/dev/bots/test.dart
+++ b/dev/bots/test.dart
@@ -66,6 +66,7 @@
   );

   await _runAllDartTests(p.join(flutterRoot, 'packages', 'flutter_driver'));

   await _runFlutterTest(p.join(flutterRoot, 'packages', 'flutter_test'));

+  await _runFlutterTest(p.join(flutterRoot, 'packages', 'flutter_markdown'));

   await _runAllDartTests(p.join(flutterRoot, 'packages', 'flutter_tools'),

       environment: <String, String>{ 'FLUTTER_ROOT': flutterRoot },

   );

diff --git a/packages/flutter_markdown/lib/src/markdown.dart b/packages/flutter_markdown/lib/src/markdown.dart
index 4012510..e995232 100644
--- a/packages/flutter_markdown/lib/src/markdown.dart
+++ b/packages/flutter_markdown/lib/src/markdown.dart
@@ -50,11 +50,14 @@
   }
 }
 
-/// A [Widget] that renders markdown formatted text. It supports all standard
-/// markdowns from the original markdown specification found here:
-/// https://daringfireball.net/projects/markdown/ This class doesn't implement
-/// any scrolling behavior, if you want scrolling either wrap the widget in
-/// a [ScrollableViewport] or use the [Markdown] widget.
+/// A [Widget] that renders markdown formatted text.
+///
+/// It supports all standard markdowns from the original markdown specification
+/// found here: <https://daringfireball.net/projects/markdown/>
+///
+/// This class doesn't implement any scrolling behavior, if you want scrolling
+/// either wrap the widget in a [SingleChildScrollView] or use the [Markdown]
+/// widget.
 class MarkdownBody extends MarkdownBodyRaw {
 
   /// Creates a new Markdown [Widget] that renders the markdown formatted string
diff --git a/packages/flutter_markdown/lib/src/markdown_raw.dart b/packages/flutter_markdown/lib/src/markdown_raw.dart
index a00d48a..0067147 100644
--- a/packages/flutter_markdown/lib/src/markdown_raw.dart
+++ b/packages/flutter_markdown/lib/src/markdown_raw.dart
@@ -80,11 +80,14 @@
   }
 }
 
-/// A [Widget] that renders markdown formatted text. It supports all standard
-/// markdowns from the original markdown specification found here:
-/// https://daringfireball.net/projects/markdown/ This class doesn't implement
-/// any scrolling behavior, if you want scrolling either wrap the widget in
-/// a [ScrollableViewport] or use the [MarkdownRaw] widget.
+/// A [Widget] that renders markdown formatted text.
+///
+/// It supports all standard markdowns from the original markdown specification
+/// found here: <https://daringfireball.net/projects/markdown/>.
+///
+/// This class doesn't implement any scrolling behavior, if you want scrolling
+/// either wrap the widget in a [SingleChildScrollView] or use the [MarkdownRaw]
+/// widget.
 class MarkdownBodyRaw extends StatefulWidget {
 
   /// Creates a new Markdown [Widget] that renders the markdown formatted string
@@ -93,7 +96,7 @@
   /// highlighting, but it's possible to pass in a custom [syntaxHighlighter].
   ///
   /// Typically, you may want to wrap the [MarkdownBodyRaw] widget in a
-  /// a [ScrollableViewport], or use the [Markdown class].
+  /// a [SingleChildScrollView], or use the [Markdown class].
   ///
   /// ```dart
   /// new SingleChildScrollView(
diff --git a/packages/flutter_markdown/test/flutter_markdown_test.dart b/packages/flutter_markdown/test/flutter_markdown_test.dart
index c72fcd7..0f5be57 100644
--- a/packages/flutter_markdown/test/flutter_markdown_test.dart
+++ b/packages/flutter_markdown/test/flutter_markdown_test.dart
@@ -9,31 +9,31 @@
 import 'package:flutter/material.dart';
 
 void main() {
-  testWidgets('Simple string', (WidgetTester tester) {
-      tester.pumpWidget(new MarkdownBody(data: 'Hello'));
+  testWidgets('Simple string', (WidgetTester tester) async {
+      await tester.pumpWidget(new MarkdownBody(data: 'Hello'));
 
       Iterable<Widget> widgets = tester.allWidgets;
       _expectWidgetTypes(widgets, <Type>[MarkdownBody, Column, Container, Padding, RichText]);
       _expectTextStrings(widgets, <String>['Hello']);
   });
 
-  testWidgets('Header', (WidgetTester tester) {
-      tester.pumpWidget(new MarkdownBody(data: '# Header'));
+  testWidgets('Header', (WidgetTester tester) async {
+      await tester.pumpWidget(new MarkdownBody(data: '# Header'));
 
       Iterable<Widget> widgets = tester.allWidgets;
       _expectWidgetTypes(widgets, <Type>[MarkdownBody, Column, Container, Padding, RichText]);
       _expectTextStrings(widgets, <String>['Header']);
   });
 
-  testWidgets('Empty string', (WidgetTester tester) {
-      tester.pumpWidget(new MarkdownBody(data: ''));
+  testWidgets('Empty string', (WidgetTester tester) async {
+      await tester.pumpWidget(new MarkdownBody(data: ''));
 
       Iterable<Widget> widgets = tester.allWidgets;
       _expectWidgetTypes(widgets, <Type>[MarkdownBody, Column]);
   });
 
-  testWidgets('Ordered list', (WidgetTester tester) {
-      tester.pumpWidget(new MarkdownBody(data: '1. Item 1\n1. Item 2\n2. Item 3'));
+  testWidgets('Ordered list', (WidgetTester tester) async {
+      await tester.pumpWidget(new MarkdownBody(data: '1. Item 1\n1. Item 2\n2. Item 3'));
 
       Iterable<Widget> widgets = tester.allWidgets;
       _expectTextStrings(widgets, <String>[
@@ -46,8 +46,8 @@
       );
   });
 
-  testWidgets('Unordered list', (WidgetTester tester) {
-      tester.pumpWidget(new MarkdownBody(data: '- Item 1\n- Item 2\n- Item 3'));
+  testWidgets('Unordered list', (WidgetTester tester) async {
+      await tester.pumpWidget(new MarkdownBody(data: '- Item 1\n- Item 2\n- Item 3'));
 
       Iterable<Widget> widgets = tester.allWidgets;
       _expectTextStrings(widgets, <String>[
@@ -60,13 +60,13 @@
       );
   });
 
-  testWidgets('Scrollable wrapping', (WidgetTester tester) {
-      tester.pumpWidget(new Markdown(data: ''));
+  testWidgets('Scrollable wrapping', (WidgetTester tester) async {
+      await tester.pumpWidget(new Markdown(data: ''));
 
       List<Widget> widgets = tester.allWidgets.toList();
       _expectWidgetTypes(widgets.take(2), <Type>[
         Markdown,
-        ScrollableViewport,
+        SingleChildScrollView,
       ]);
       _expectWidgetTypes(widgets.reversed.take(3).toList().reversed, <Type>[
         Padding,
@@ -75,8 +75,8 @@
       ]);
   });
 
-  testWidgets('Links', (WidgetTester tester) {
-      tester.pumpWidget(new Markdown(data: '[Link Text](href)'));
+  testWidgets('Links', (WidgetTester tester) async {
+      await tester.pumpWidget(new Markdown(data: '[Link Text](href)'));
 
       RichText textWidget = tester.allWidgets.firstWhere((Widget widget) => widget is RichText);
       TextSpan span = textWidget.text;
@@ -84,29 +84,29 @@
       expect(span.children[0].recognizer.runtimeType, equals(TapGestureRecognizer));
   });
 
-  testWidgets('Changing config - data', (WidgetTester tester) {
-      tester.pumpWidget(new Markdown(data: 'Data1'));
+  testWidgets('Changing config - data', (WidgetTester tester) async {
+      await tester.pumpWidget(new Markdown(data: 'Data1'));
       _expectTextStrings(tester.allWidgets, <String>['Data1']);
 
       String stateBefore = WidgetsBinding.instance.renderViewElement.toStringDeep();
-      tester.pumpWidget(new Markdown(data: 'Data1'));
+      await tester.pumpWidget(new Markdown(data: 'Data1'));
       String stateAfter = WidgetsBinding.instance.renderViewElement.toStringDeep();
       expect(stateBefore, equals(stateAfter));
 
-      tester.pumpWidget(new Markdown(data: 'Data2'));
+      await tester.pumpWidget(new Markdown(data: 'Data2'));
       _expectTextStrings(tester.allWidgets, <String>['Data2']);
   });
 
-  testWidgets('Changing config - style', (WidgetTester tester) {
+  testWidgets('Changing config - style', (WidgetTester tester) async {
       ThemeData theme = new ThemeData.light();
 
       MarkdownStyle style1 = new MarkdownStyle.defaultFromTheme(theme);
       MarkdownStyle style2 = new MarkdownStyle.largeFromTheme(theme);
 
-      tester.pumpWidget(new Markdown(data: 'Test', markdownStyle: style1));
+      await tester.pumpWidget(new Markdown(data: 'Test', markdownStyle: style1));
 
       String stateBefore = WidgetsBinding.instance.renderViewElement.toStringDeep();
-      tester.pumpWidget(new Markdown(data: 'Test', markdownStyle: style2));
+      await tester.pumpWidget(new Markdown(data: 'Test', markdownStyle: style2));
       String stateAfter = WidgetsBinding.instance.renderViewElement.toStringDeep();
       expect(stateBefore, isNot(stateAfter));
   });