test: add color tag tests

The majority of the uses of strong-log-transformer are for prefixing
console output from multiple processes with a child process identifier
and almost all of them make use of ANSI escape codes in the tags so that
the output is suitably colorful. Since that's a common use, these tests
will ensure that the current behaviour doesn't accidentally change.

Signed-off-by: Ryan Graham <[email protected]>

Author: rmg

test/test-ansi-color-tags.js

@@ -0,0 +1,65 @@
+var tap = require('tap');
+var Log = require('../');
+
+tap.test('tag object with ansi escape codes', function(t) {
+  var slt = Log({
+    tag: {
+      blue: '\u001b[1m\u001b[34mblue\u001b[39m\u001b[22m',
+      green: '\u001b[32mgreen\u001b[39m',
+    },
+  });
+  var input = [
+    'good line',
+    'good line',
+    'good line',
+  ];
+  var expected = input.map(function(line) {
+    return 'blue:\u001b[1m\u001b[34mblue\u001b[39m\u001b[22m green:\u001b[32mgreen\u001b[39m ' + line + '\n';
+  }).join('');
+  var received = '';
+
+  slt.on('data', function(buf) {
+    t.comment(buf);
+    if (Buffer.isBuffer(buf)) {
+      received += buf.toString('utf8');
+    } else if (buf !== null) {
+      received += buf;
+    }
+  });
+  slt.on('end', function() {
+    t.same(received, expected, 'output is input + trailing newline');
+    t.end();
+  });
+  slt.write(input.join('\n'));
+  slt.end();
+});
+
+tap.test('tag string with ansi escape codes', function(t) {
+  var slt = Log({
+    tag: '\u001b[1m\u001b[34mblue\u001b[39m\u001b[22m',
+  });
+  var input = [
+    'good line',
+    'good line',
+    'good line',
+  ];
+  var expected = input.map(function(line) {
+    return '\u001b[1m\u001b[34mblue\u001b[39m\u001b[22m ' + line + '\n';
+  }).join('');
+  var received = '';
+
+  slt.on('data', function(buf) {
+    t.comment(buf);
+    if (Buffer.isBuffer(buf)) {
+      received += buf.toString('utf8');
+    } else if (buf !== null) {
+      received += buf;
+    }
+  });
+  slt.on('end', function() {
+    t.same(received, expected, 'output is input + trailing newline');
+    t.end();
+  });
+  slt.write(input.join('\n'));
+  slt.end();
+});