Properly generate code for parameter default value Strings.

Fixes #756

In order to properly allow single quotes and dollar signs in parameter default values, we must not print as raw, and we must escape dollar signs ourselves, before passing to code_builder.

PiperOrigin-RevId: 646140324

lib/src/builder.dart

@@ -1822,7 +1822,11 @@ class _MockClassInfo {
     } else if (constant.isInt) {
       return literalNum(constant.intValue);
     } else if (constant.isString) {
-      return literalString(constant.stringValue, raw: true);
+      // code_builder writes all strings with single quotes.
+      // Raw single quoted strings may not contain single quotes,
+      // so escape dollar signs and use a non-raw string instead.
+      final stringValue = constant.stringValue.replaceAll('\$', '\\\$');
+      return literalString(stringValue);
     } else if (constant.isList) {
       return literalConstList([
         for (final element in constant.listValue)

test/builder/auto_mocks_test.dart

@@ -281,13 +281,46 @@ void main() {
     await expectSingleNonNullableOutput(
       dedent(r'''
       class Foo {
-        void m([String a = 'Hello', String b = 'Hello ' r"World"]) {}
+        void m([String a = 'Hello', String b = "World"]) {}
       }
       '''),
       _containsAllOf(dedent2('''
         void m([
-          String? a = r'Hello',
-          String? b = r'Hello World',
+          String? a = 'Hello',
+          String? b = 'World',
+        ]) =>
+        ''')),
+    );
+  });
+
+  test('matches string literal parameter default values with quote characters',
+      () async {
+    await expectSingleNonNullableOutput(
+      dedent(r'''
+      class Foo {
+        void m([String a = 'Hel"lo', String b = "Wor'ld"]) {}
+      }
+      '''),
+      _containsAllOf(dedent2('''
+        void m([
+          String? a = 'Hel"lo',
+          String? b = 'Wor\\'ld',
+        ]) =>
+        ''')),
+    );
+  });
+
+  test('matches raw string literal parameter default values', () async {
+    await expectSingleNonNullableOutput(
+      dedent(r'''
+      class Foo {
+        void m([String a = r'$Hello', String b = r"$World"]) {}
+      }
+      '''),
+      _containsAllOf(dedent2('''
+        void m([
+          String? a = '\\\$Hello',
+          String? b = '\\\$World',
         ]) =>
         ''')),
     );
@@ -337,8 +370,8 @@ void main() {
       _containsAllOf(dedent2('''
         void m(
                 [Map<int, String>? a = const {
-                  1: r'a',
-                  2: r'b',
+                  1: 'a',
+                  2: 'b',
                 }]) =>
         ''')),
     );
@@ -354,8 +387,8 @@ void main() {
       _containsAllOf(dedent2('''
         void m(
                 [Map<int, String>? a = const {
-                  1: r'a',
-                  2: r'b',
+                  1: 'a',
+                  2: 'b',
                 }]) =>
         ''')),
     );