[dartdev] address a few analysis issues

Change-Id: I546a88aeed31a3e7349a45825087e3bed4720559
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/138913
Reviewed-by: Jaime Wren <jwren@google.com>
Commit-Queue: Devon Carew <devoncarew@google.com>

pkg/dartdev/analysis_options.yaml

@@ -1 +1,14 @@
 include: package:pedantic/analysis_options.1.8.0.yaml
+
+analyzer:
+  errors:
+    # Increase the severity of several hints.
+    prefer_single_quotes: warning
+    unused_import: warning
+    unnecessary_brace_in_string_interps: warning
+
+linter:
+  rules:
+    - directives_ordering
+    - prefer_single_quotes
+    - unnecessary_brace_in_string_interps

pkg/dartdev/lib/src/commands/analyze.dart

@@ -32,7 +32,7 @@ class AnalyzeCommand extends DartdevCommand<int> {
   @override
   FutureOr<int> run() async {
     if (argResults.rest.length > 1) {
-      usageException("Only one directory is expected.");
+      usageException('Only one directory is expected.');
     }
 
     // find directory from argResults.rest

pkg/dartdev/test/commands/analyze_test.dart

@@ -87,10 +87,10 @@ void defineAnalyze() {
 
     expect(result.exitCode, 3);
     expect(result.stderr, isEmpty);
-    expect(result.stdout, contains("A value of type "));
-    expect(result.stdout, contains("lib/main.dart:1:16 "));
-    expect(result.stdout, contains("return_of_invalid_type"));
-    expect(result.stdout, contains("1 issue found."));
+    expect(result.stdout, contains('A value of type '));
+    expect(result.stdout, contains('lib/main.dart:1:16 '));
+    expect(result.stdout, contains('return_of_invalid_type'));
+    expect(result.stdout, contains('1 issue found.'));
   });
 
   test('two errors', () {
@@ -99,7 +99,7 @@ void defineAnalyze() {
 
     expect(result.exitCode, 3);
     expect(result.stderr, isEmpty);
-    expect(result.stdout, contains("2 issues found."));
+    expect(result.stdout, contains('2 issues found.'));
   });
 
   test('warning --fatal-warnings', () {
@@ -110,7 +110,7 @@ void defineAnalyze() {
     //  should be exitCode == 2, not greater than 0:
     expect(result.exitCode, greaterThan(0));
     expect(result.stderr, isEmpty);
-    expect(result.stdout, contains("1 issue found."));
+    expect(result.stdout, contains('1 issue found.'));
   });
 
   test('warning implicit --fatal-warnings', () {
@@ -121,7 +121,7 @@ void defineAnalyze() {
     //  should be exitCode == 2, not greater than 0:
     expect(result.exitCode, greaterThan(0));
     expect(result.stderr, isEmpty);
-    expect(result.stdout, contains("1 issue found."));
+    expect(result.stdout, contains('1 issue found.'));
   });
 
   test('warning --no-fatal-warnings', () {
@@ -132,24 +132,24 @@ void defineAnalyze() {
     //  should be exitCode == 0:
     // expect(result.exitCode, 0);
     expect(result.stderr, isEmpty);
-    expect(result.stdout, contains("1 issue found."));
+    expect(result.stdout, contains('1 issue found.'));
   });
 
   test('info implicit no --fatal-infos', () {
-    p = project(mainSrc: "String foo() {}");
+    p = project(mainSrc: 'String foo() {}');
     var result = p.runSync('analyze', [p.dirPath]);
 
     expect(result.exitCode, 0);
     expect(result.stderr, isEmpty);
-    expect(result.stdout, contains("1 issue found."));
+    expect(result.stdout, contains('1 issue found.'));
   });
 
   test('info --fatal-infos', () {
-    p = project(mainSrc: "String foo() {}");
+    p = project(mainSrc: 'String foo() {}');
     var result = p.runSync('analyze', ['--fatal-infos', p.dirPath]);
 
     expect(result.exitCode, 1);
     expect(result.stderr, isEmpty);
-    expect(result.stdout, contains("1 issue found."));
+    expect(result.stdout, contains('1 issue found.'));
   });
 }

pkg/dartdev/test/commands/format_test.dart

@@ -75,7 +75,7 @@ void format() {
     ProcessResult result = p.runSync('format', [unknownFilePath]);
     expect(result.exitCode, 0);
     expect(result.stderr,
-        startsWith('No file or directory found at "${unknownFilePath}".'));
+        startsWith('No file or directory found at "$unknownFilePath".'));
     expect(result.stdout, isEmpty);
   });
 }