diff --git a/test/dcat_test.dart b/test/dcat_test.dart
index fd1ec4e..90971b5 100644
--- a/test/dcat_test.dart
+++ b/test/dcat_test.dart
@@ -47,119 +47,40 @@ void main() {
       expect(exitCode, exitFailure);
     });
 
-    test('no directories', () async {
-      exitCode = await app.main(['bin']);
-      expect(exitCode, exitFailure);
-    });
-
     test('missing file', () async {
       exitCode = await app.main(['foo']);
       expect(exitCode, exitFailure, reason: 'foo not found');
       exitCode = await app.main([sourceFile, 'foo']);
       expect(exitCode, exitFailure, reason: 'one missing file');
     });
+
+    test('no directories', () async {
+      exitCode = await app.main(['bin']);
+      expect(exitCode, exitFailure);
+    });
   });
 
   group('lib', () {
     test('CatResult defaults', () async {
       final result = CatResult();
       expect(result.isSuccess, true, reason: 'success by default');
-      result.addMessage(exitFailure, sampleText);
+      expect(result.messages.isEmpty, true, reason: 'empty by default');
+      result.addMessage(sampleText);
       expect(result.isFailure, true, reason: 'is failure');
       expect(result.messages.first, equals(sampleText),
           reason: 'message is sample');
+      final path = 'foo/bar';
+      result.addMessage(sampleText, path: path);
+      expect(result.messages.last, equals("$path: $sampleText"), reason: 'message has path');
     });
 
-    test('cat source', () async {
-      final tmp = makeTmpFile();
-      await cat([sourceFile], tmp.openWrite());
-      final lines = await tmp.readAsLines();
-      expect(lines.isEmpty, false, reason: 'log is empty');
-      expect(lines.first, startsWith('// Copyright (c)'),
-          reason: 'has copyright');
-      expect(lines.last, equals('}'));
-    });
-
-    test('cat -n source', () async {
-      final tmp = makeTmpFile();
-      final result =
-          await cat([sourceFile], tmp.openWrite(), showLineNumbers: true);
-      expect(result.exitCode, 0, reason: 'result code is 0');
-      final lines = await tmp.readAsLines();
-      expect(lines.first, startsWith('     1\t// Copyright (c)'),
-          reason: 'has copyright');
-      expect(lines.last, endsWith('\t}'), reason: 'last line');
-      for (final line in lines) {
-        expect(line, matches('^ +\\d+\t.*'), reason: 'has line number');
-      }
-    });
-
-    test('cat source, test', () async {
-      final tmp = makeTmpFile();
-      await cat([sourceFile, sampleFile], tmp.openWrite());
-      final lines = await tmp.readAsLines();
-      expect(lines.length, greaterThan(10), reason: 'more than 10 lines');
-      expect(lines.first, startsWith('// Copyright'),
-          reason: 'start with copyright');
-      expect(lines.last, endsWith('✓'), reason: 'end with checkmark');
-    });
-
-    test('cat -E', () async {
-      final tmp = makeTmpFile();
-      await cat([sampleFile], tmp.openWrite(), showEnds: true);
-      var hasBlank = false;
-      final lines = await tmp.readAsLines();
-      for (var i = 0; i < lines.length - 1; i++) {
-        expect(lines[i], endsWith('\$'));
-        if (lines[i] == '\$') {
-          hasBlank = true;
-        }
-      }
-      expect(hasBlank, true, reason: 'has blank line');
-      expect(lines.last, endsWith('✓'), reason: 'has unicode');
-    });
-
-    test('cat -bE', () async {
-      final tmp = makeTmpFile();
-      await cat([sampleFile], tmp.openWrite(),
-          numberNonBlank: true, showEnds: true);
-      final lines = await tmp.readAsLines();
-      for (var i = 0; i < lines.length - 1; i++) {
-        expect(lines[i], endsWith('\$'), reason: '${lines[i]} ends with \$');
-        if (lines[i] != '\$') {
-          expect(lines[i], contains(RegExp(r'^ +\d+\t.*\$$')),
-              reason: '${lines[i]} is valid');
-        }
-      }
-    });
-
-    test('cat -T', () async {
-      final tmp = makeTmpFile();
-      await cat([sampleFile], tmp.openWrite(), showTabs: true);
-      var hasTab = false;
-      final lines = await tmp.readAsLines();
-      for (final String line in lines) {
-        if (line.startsWith('^I')) {
-          hasTab = true;
-          break;
-        }
-      }
-      expect(hasTab, true, reason: 'has tab');
-    });
-
-    test('cat -s', () async {
-      final tmp = makeTmpFile();
-      await cat([sampleFile], tmp.openWrite(), squeezeBlank: true);
-      var hasSqueeze = true;
-      var prevLine = 'foo';
-      final lines = await tmp.readAsLines();
-      for (final String line in lines) {
-        if (line == prevLine) {
-          hasSqueeze = false;
-        }
-        prevLine = line;
-      }
-      expect(hasSqueeze, true, reason: 'has squeeze');
+    test('cat -', () async {
+      var tmp = makeTmpFile();
+      final result = await cat(['-'], tmp.openWrite(), input: mockStdin());
+      expect(result.exitCode, exitSuccess, reason: 'result code is successful');
+      expect(result.messages.length, 0, reason: 'no message');
+      tmp = makeTmpFile();
+      expect(await tmp.exists(), false, reason: 'tmp file does not exists');
     });
 
     test('cat -A', () async {
@@ -172,14 +93,6 @@ void main() {
           reason: "no last linefeed");
     });
 
-    test('cat -t', () async {
-      final tmp = makeTmpFile();
-      await cat([sampleFile], tmp.openWrite(),
-          showNonPrinting: true, showTabs: true);
-      final lines = await tmp.readAsLines();
-      expect(lines.last, equals('^I^A^B^C^DM-BM-)^?M-BM-^@M-bM-^\\M-^S'));
-    });
-
     test('cat -Abs', () async {
       final tmp = makeTmpFile();
       await cat([sampleFile], tmp.openWrite(),
@@ -198,6 +111,94 @@ void main() {
       expect(blankLines, 2, reason: 'only 2 blank lines.');
     });
 
+    test('cat -E', () async {
+      final tmp = makeTmpFile();
+      await cat([sampleFile], tmp.openWrite(), showEnds: true);
+      var hasBlank = false;
+      final lines = await tmp.readAsLines();
+      for (var i = 0; i < lines.length - 1; i++) {
+        expect(lines[i], endsWith('\$'));
+        if (lines[i] == '\$') {
+          hasBlank = true;
+        }
+      }
+      expect(hasBlank, true, reason: 'has blank line');
+      expect(lines.last, endsWith('✓'), reason: 'has unicode');
+    });
+
+    test('cat -T', () async {
+      final tmp = makeTmpFile();
+      await cat([sampleFile], tmp.openWrite(), showTabs: true);
+      var hasTab = false;
+      final lines = await tmp.readAsLines();
+      for (final String line in lines) {
+        if (line.startsWith('^I')) {
+          hasTab = true;
+          break;
+        }
+      }
+      expect(hasTab, true, reason: 'has tab');
+    });
+
+    test('cat -bE', () async {
+      final tmp = makeTmpFile();
+      await cat([sampleFile], tmp.openWrite(),
+          numberNonBlank: true, showEnds: true);
+      final lines = await tmp.readAsLines();
+      for (var i = 0; i < lines.length - 1; i++) {
+        expect(lines[i], endsWith('\$'), reason: '${lines[i]} ends with \$');
+        if (lines[i] != '\$') {
+          expect(lines[i], contains(RegExp(r'^ +\d+\t.*\$$')),
+              reason: '${lines[i]} is valid');
+        }
+      }
+    });
+
+    test('cat -n source', () async {
+      final tmp = makeTmpFile();
+      final result =
+          await cat([sourceFile], tmp.openWrite(), showLineNumbers: true);
+      expect(result.exitCode, 0, reason: 'result code is 0');
+      final lines = await tmp.readAsLines();
+      expect(lines.first, startsWith('     1\t// Copyright (c)'),
+          reason: 'has copyright');
+      expect(lines.last, endsWith('\t}'), reason: 'last line');
+      for (final line in lines) {
+        expect(line, matches('^ +\\d+\t.*'), reason: 'has line number');
+      }
+    });
+
+    test('cat -s', () async {
+      final tmp = makeTmpFile();
+      await cat([sampleFile], tmp.openWrite(), squeezeBlank: true);
+      var hasSqueeze = true;
+      var prevLine = 'foo';
+      final lines = await tmp.readAsLines();
+      for (final String line in lines) {
+        if (line == prevLine) {
+          hasSqueeze = false;
+        }
+        prevLine = line;
+      }
+      expect(hasSqueeze, true, reason: 'has squeeze');
+    });
+
+    test('cat -t', () async {
+      final tmp = makeTmpFile();
+      await cat([sampleFile], tmp.openWrite(),
+          showNonPrinting: true, showTabs: true);
+      final lines = await tmp.readAsLines();
+      expect(lines.last, equals('^I^A^B^C^DM-BM-)^?M-BM-^@M-bM-^\\M-^S'));
+    });
+
+    test('cat -v binary, file', () async {
+      final tmp = makeTmpFile();
+      await cat([sampleBinary, sampleFile], tmp.openWrite(),
+          showNonPrinting: true);
+      var lines = await tmp.readAsLines();
+      expect(lines.first, startsWith('7z'));
+    });
+
     test('cat -v', () async {
       final tmp = makeTmpFile();
       await cat([sampleFile], tmp.openWrite(), showNonPrinting: true);
@@ -227,38 +228,38 @@ void main() {
       expect(lines.last, endsWith('✓'), reason: 'end with checkmark');
     });
 
-    test('cat -v binary, file', () async {
-      final tmp = makeTmpFile();
-      await cat([sampleBinary, sampleFile], tmp.openWrite(),
-          showNonPrinting: true);
-      var lines = await tmp.readAsLines();
-      expect(lines.first, startsWith('7z'));
-    });
-
     test('cat binary', () async {
       final tmp = makeTmpFile();
       await cat([sampleBinary], tmp.openWrite());
       expect(tmp.readAsLines(), throwsException);
     });
 
-    test('empty stdin', () async {
-      final tmp = makeTmpFile();
-      var result = await cat([], tmp.openWrite(), input: Stream.empty());
-      expect(result.exitCode, exitSuccess, reason: 'cat() is successful');
-      expect(result.messages.length, 0, reason: 'cat() has no message');
-
-      result = await cat(['-'], tmp.openWrite(), input: Stream.empty());
-      expect(result.exitCode, exitSuccess, reason: 'cat(-) is successful');
-      expect(result.messages.length, 0, reason: 'cat(-) no message');
+    test('cat file -', () async {
+      var tmp = makeTmpFile();
+      await cat([sampleFile, '-'], tmp.openWrite(),
+          input: mockStdin(text: '\n$sampleText'));
+      var lines = await tmp.readAsLines();
+      expect(lines.last, equals(sampleText));
     });
 
-    test('cat -', () async {
-      var tmp = makeTmpFile();
-      final result = await cat(['-'], tmp.openWrite(), input: mockStdin());
-      expect(result.exitCode, exitSuccess, reason: 'result code is successful');
-      expect(result.messages.length, 0, reason: 'no message');
-      tmp = makeTmpFile();
-      expect(await tmp.exists(), false, reason: 'tmp file does not exists');
+    test('cat source', () async {
+      final tmp = makeTmpFile();
+      await cat([sourceFile], tmp.openWrite());
+      final lines = await tmp.readAsLines();
+      expect(lines.isEmpty, false, reason: 'log is empty');
+      expect(lines.first, startsWith('// Copyright (c)'),
+          reason: 'has copyright');
+      expect(lines.last, equals('}'));
+    });
+
+    test('cat source, test', () async {
+      final tmp = makeTmpFile();
+      await cat([sourceFile, sampleFile], tmp.openWrite());
+      final lines = await tmp.readAsLines();
+      expect(lines.length, greaterThan(10), reason: 'more than 10 lines');
+      expect(lines.first, startsWith('// Copyright'),
+          reason: 'start with copyright');
+      expect(lines.last, endsWith('✓'), reason: 'end with checkmark');
     });
 
     test('cat()', () async {
@@ -272,14 +273,6 @@ void main() {
       expect(lines.length, 2, reason: "two lines");
     });
 
-    test('cat file -', () async {
-      var tmp = makeTmpFile();
-      await cat([sampleFile, '-'], tmp.openWrite(),
-          input: mockStdin(text: '\n$sampleText'));
-      var lines = await tmp.readAsLines();
-      expect(lines.last, equals(sampleText));
-    });
-
     test('closed stdout', () async {
       final tmp = makeTmpFile();
       final stream = tmp.openWrite();
@@ -287,5 +280,21 @@ void main() {
       final result = await cat([sampleFile], stream);
       expect(result.messages.first, contains("closed"));
     });
+
+    test('empty stdin', () async {
+      final tmp = makeTmpFile();
+      var result = await cat([], tmp.openWrite(), input: Stream.empty());
+      expect(result.exitCode, exitSuccess, reason: 'cat() is successful');
+      expect(result.messages.length, 0, reason: 'cat() has no message');
+      result = await cat(['-'], tmp.openWrite(), input: Stream.empty());
+      expect(result.exitCode, exitSuccess, reason: 'cat(-) is successful');
+      expect(result.messages.length, 0, reason: 'cat(-) no message');
+    });
+
+    test('invalid stdin', () async {
+      final tmp = makeTmpFile();
+      final result = await cat([], tmp.openWrite(), input: null);
+      expect(result.exitCode, exitSuccess);
+    });
   });
 }