Use generated tests instead files.

build.dart

@@ -0,0 +1,14 @@
+library md_proc.build_file;
+
+import 'package:source_gen/source_gen.dart';
+import 'package:md_proc/generators/embed_tests_generator.dart';
+
+void main(List<String> args) {
+  build(args, const [
+    const EmbedTestsGenerator()
+  ], librarySearchPaths: [
+    'test'
+  ]).then((msg) {
+    print(msg);
+  });
+}

lib/generators/embed_tests.dart

@@ -0,0 +1,7 @@
+library md_proc.generators.embed_tests;
+
+class EmbedTests {
+  final String path;
+
+  const EmbedTests(this.path);
+}

lib/generators/embed_tests_generator.dart

@@ -0,0 +1,83 @@
+library md_proc.generators.embed_tests_generator;
+
+import 'dart:async';
+import 'dart:io';
+
+import 'package:analyzer/src/generated/element.dart';
+import 'package:analyzer/src/generated/source_io.dart';
+import 'package:path/path.dart' as path;
+import 'package:source_gen/source_gen.dart';
+
+import 'embed_tests.dart';
+
+
+class EmbedTestsGenerator extends GeneratorForAnnotation<EmbedTests> {
+  static const int stateWait = 0;
+  static const int stateSource = 1;
+  static const int stateDestination = 2;
+
+  @override
+  final AssociatedFileSet associatedFileSet;
+
+  /// If [associatedFileSet] is not set, the default value of
+  /// [AssociatedFileSet.sameDirectory] is used.
+  const EmbedTestsGenerator(
+      {AssociatedFileSet associatedFileSet: AssociatedFileSet.sameDirectory})
+      : this.associatedFileSet = associatedFileSet;
+
+  Map<String, String> readFile(fileName) {
+    Map<String, String> result = <String, String>{};
+
+    File file = new File(fileName);
+    int state = stateWait;
+    List<String> destination = [];
+    List<String> source = [];
+    List<String> lines = file.readAsLinesSync();
+    for (String line in lines) {
+      if (line == ".") {
+        state++;
+        if (state == 3) {
+          result[source.map((line) => line + "\n").join()] = destination.map((line) => line + "\n").join();
+          state = stateWait;
+          destination = [];
+          source = [];
+        }
+      } else if (state == stateSource) {
+        source.add(line);
+      } else if (state == stateDestination) {
+        destination.add(line);
+      }
+    }
+
+    return result;
+  }
+
+  @override
+  Future<String> generateForAnnotatedElement(
+      Element element, EmbedTests annotation) async {
+    if (path.isAbsolute(annotation.path)) {
+      throw 'must be relative path to the source file';
+    }
+
+    var source = element.source as FileBasedSource;
+    var sourcePath = source.file.getAbsolutePath();
+
+    var sourcePathDir = path.dirname(sourcePath);
+
+    var filePath = path.join(sourcePathDir, annotation.path);
+
+    if (!await FileSystemEntity.isFile(filePath)) {
+      throw 'Not a file! - $filePath';
+    }
+
+    var content = readFile(filePath);
+
+    var result = 'final Map<String, String> _\$${element.displayName}Tests = {\n';
+    content.forEach((k, v) {
+      result += "r'''" + k + "''': r'''" + v + "''',\n";
+    });
+    result += '};\n';
+
+    return result;
+  }
+}

pubspec.yaml

@@ -13,4 +13,4 @@ dev_dependencies:
   test: any
   linter: any
   dart_coveralls: any
-
+  source_gen: '>=0.4.2 <0.5.0'

test/data/test_data.dart

@@ -0,0 +1,17 @@
+library md_proc.test.data.test_data;
+
+import 'package:md_proc/generators/embed_tests.dart';
+
+part 'test_data.g.dart';
+
+@EmbedTests('spec.txt')
+final Map<String, String> specification = _$specificationTests;
+
+@EmbedTests('smart_punct.txt')
+final Map<String, String> smartPunctuation = _$smartPunctuationTests;
+
+@EmbedTests('markdownToMarkdown.txt')
+final Map<String, String> markdownToMarkdown = _$markdownToMarkdownTests;
+
+@EmbedTests('additionalMarkdownToHtml.txt')
+final Map<String, String> additionalMarkdownToHtml = _$additionalMarkdownToHtmlTests;