Scrap more packages (#3488)

diff --git a/.gitignore b/.gitignore
index 0454e79..b594341 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,5 +1,5 @@
 .idea
-.dart_tool
+/.dart_tool
 packages
 build
 .project
diff --git a/lib/src/test_utilities/test_resource_provider.dart b/lib/src/test_utilities/test_resource_provider.dart
index 64ba18a..696c1ee 100644
--- a/lib/src/test_utilities/test_resource_provider.dart
+++ b/lib/src/test_utilities/test_resource_provider.dart
@@ -20,13 +20,6 @@
       context: PhysicalResourceProvider.INSTANCE.pathContext);
   var resourceProvider = TestResourceProvider(memoryResourceProvider);
 
-  var pathContext = memoryResourceProvider.pathContext;
-  String? packageConfigPath = memoryResourceProvider.convertPath(pathContext
-      .join(pathContext.dirname(file.absolute.path), '.mock_packages'));
-  if (!resourceProvider.getFile(packageConfigPath).exists) {
-    packageConfigPath = null;
-  }
-
   var sdkRoot = memoryResourceProvider.getFolder(
     memoryResourceProvider.convertPath('/sdk'),
   );
@@ -37,8 +30,7 @@
 
   var options = LinterOptions([rule], analysisOptions)
     ..dartSdkPath = sdkRoot.path
-    ..resourceProvider = resourceProvider
-    ..packageConfigPath = packageConfigPath;
+    ..resourceProvider = resourceProvider;
 
   return DartLinter(options);
 }
diff --git a/test/integration/prefer_const_constructors.dart b/test/integration/prefer_const_constructors.dart
index 0ba65ab..362c0c6 100644
--- a/test/integration/prefer_const_constructors.dart
+++ b/test/integration/prefer_const_constructors.dart
@@ -30,8 +30,6 @@
       await cli.runLinter([
         '$integrationTestDir/prefer_const_constructors',
         '--rules=prefer_const_constructors',
-        '--packages',
-        '$ruleTestDir/.mock_packages',
       ], LinterOptions());
       expect(
           collectingOut.trim(),
diff --git a/test/integration/prefer_mixin.dart b/test/integration/prefer_mixin.dart
index 151beff..d10152a 100644
--- a/test/integration/prefer_mixin.dart
+++ b/test/integration/prefer_mixin.dart
@@ -30,8 +30,6 @@
       await cli.runLinter([
         '$integrationTestDir/prefer_mixin',
         '--rules=prefer_mixin',
-        '--packages',
-        '$ruleTestDir/.mock_packages',
       ], LinterOptions());
       expect(
           collectingOut.trim(),
diff --git a/test_data/rules/.dart_tool/package_config.json b/test_data/rules/.dart_tool/package_config.json
new file mode 100644
index 0000000..c35b162
--- /dev/null
+++ b/test_data/rules/.dart_tool/package_config.json
@@ -0,0 +1,32 @@
+{
+  "configVersion": 2,
+  "packages": [
+    {
+      "name": "fixnum",
+      "rootUri": "../../mock_packages/fixnum/",
+      "packageUri": "lib/",
+      "languageVersion": "2.17"
+    },
+    {
+      "name": "flutter",
+      "rootUri": "../../mock_packages/flutter/",
+      "packageUri": "lib/",
+      "languageVersion": "2.17"
+    },
+    {
+      "name": "meta",
+      "rootUri": "../../mock_packages/meta/",
+      "packageUri": "lib/",
+      "languageVersion": "2.17"
+    },
+    {
+      "name": "test_api",
+      "rootUri": "../../mock_packages/test_api/",
+      "packageUri": "lib/",
+      "languageVersion": "2.17"
+    }
+  ],
+  "generated": "2022-06-30T01:27:31.576781Z",
+  "generator": "pub",
+  "generatorVersion": "2.17.0"
+}
diff --git a/test_data/rules/.mock_packages b/test_data/rules/.mock_packages
deleted file mode 100644
index fe1c463..0000000
--- a/test_data/rules/.mock_packages
+++ /dev/null
@@ -1,4 +0,0 @@
-fixnum:../mock_packages/fixnum/lib/
-flutter:../mock_packages/flutter/lib/
-meta:../mock_packages/meta/lib/
-test_api:../mock_packages/test_api/lib/