fix: avoid failure when terminal has no columns (#869)

Author: alestiago

lib/src/logger_extension.dart

@@ -1,6 +1,16 @@
+import 'dart:io';
 import 'package:mason_logger/mason_logger.dart';
+import 'package:meta/meta.dart';
 import 'package:universal_io/io.dart';
 
+/// The fallback number of columns of the terminal.
+///
+/// Used when the terminal number of columns (width) cannot be determined. For
+/// example, when running in Azure DevOps, see relevant issue:
+/// https://github.com/VeryGoodOpenSource/very_good_cli/issues/866 .
+@visibleForTesting
+const fallbackStdoutTerminalColumns = 80;
+
 /// Extension on the Logger class for custom styled logging.
 extension LoggerX on Logger {
   /// Log a message in the "created" style of the CLI.
@@ -11,13 +21,22 @@ extension LoggerX on Logger {
   /// Wrap the [text] to fit perfectly within the width of the terminal when
   /// [print]ed.
   ///
-  /// To overwrite the width you can use [length].
+  /// The text will wrap around the terminal width, and will not break words. If
+  /// the terminal width cannot be determined, the text will wrap around the
+  /// [fallbackStdoutTerminalColumns].
+  ///
+  /// To completely overwrite the width you can use [length].
   void wrap(
     String? text, {
     required void Function(String?) print,
     int? length,
   }) {
-    final maxLength = length ?? stdout.terminalColumns;
+    final maxLength = switch (length) {
+      == null when stdout.hasTerminal => stdout.terminalColumns,
+      == null when !stdout.hasTerminal => fallbackStdoutTerminalColumns,
+      _ => length!
+    };
+
     for (final sentence in text?.split('/n') ?? <String>[]) {
       final words = sentence.split(' ');
 

test/src/command_runner_test.dart

@@ -199,6 +199,7 @@ void main() {
           when(() => versionFile.readAsStringSync()).thenReturn('0.0.0');
 
           stdout = _MockStdout();
+          when(() => stdout.hasTerminal).thenReturn(true);
           when(() => stdout.supportsAnsiEscapes).thenReturn(true);
           when(() => stdout.terminalColumns).thenReturn(30);
         });

test/src/logger_extension_test.dart

@@ -1,16 +1,23 @@
 import 'package:mason/mason.dart';
 import 'package:mocktail/mocktail.dart';
 import 'package:test/test.dart';
+import 'package:universal_io/io.dart';
 import 'package:very_good_cli/src/logger_extension.dart';
 
 class _MockLogger extends Mock implements Logger {}
 
+class _MockStdout extends Mock implements Stdout {}
+
 void main() {
   group('LoggerX', () {
     late Logger logger;
+    late Stdout stdout;
 
     setUp(() {
       logger = _MockLogger();
+      stdout = _MockStdout();
+
+      when(() => stdout.hasTerminal).thenReturn(true);
     });
 
     test('created', () {
@@ -45,6 +52,57 @@ void main() {
           () => logger.info(any(that: equals('1 2 3 4 5 '))),
         ]);
       });
+
+      test(
+        '''defaults to `fallbackStdoutTerminalColumns` when there is no terminal''',
+        () async {
+          await IOOverrides.runZoned(
+            stdout: () => stdout,
+            () async {
+              when(() => stdout.hasTerminal).thenReturn(false);
+              const stdoutException = StdoutException('');
+              when(() => stdout.terminalColumns).thenThrow(stdoutException);
+
+              final longWord = Iterable.generate(
+                fallbackStdoutTerminalColumns,
+                (_) => '1',
+              ).join();
+              const shortWord = '1';
+
+              logger.wrap('$longWord $shortWord', print: logger.info);
+
+              verifyInOrder([
+                () => logger.info(
+                      any(
+                        that: equals('$longWord '),
+                      ),
+                    ),
+                () => logger.info(
+                      any(that: equals('$shortWord ')),
+                    ),
+              ]);
+            },
+          );
+        },
+      );
+
+      test(
+        '''throws when an unknown exception occurs when reading `stdout.terminalColumns`''',
+        () async {
+          await IOOverrides.runZoned(
+            stdout: () => stdout,
+            () async {
+              final unknownException = Exception();
+              when(() => stdout.terminalColumns).thenThrow(unknownException);
+
+              expect(
+                () => logger.wrap('test', print: logger.info),
+                throwsA(equals(unknownException)),
+              );
+            },
+          );
+        },
+      );
     });
   });
 }