[Gradle, JS] Add custom log4js appender for karma

#KT-38109 fixed

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/testing/karma/KotlinKarma.kt

@@ -79,6 +79,9 @@ class KotlinKarma(override val compilation: KotlinJsCompilation) :
                 config.plugins = config.plugins || [];
                 config.plugins.push('karma-*'); // default
                 config.plugins.push('kotlin-test-js-runner/karma-kotlin-reporter.js');
+                
+                config.loggers = config.loggers || [];
+                config.loggers.push({type: 'kotlin-test-js-runner/tc-log-appender.js'});
             """.trimIndent()
             )
         }

libraries/tools/kotlin-test-js-runner/rollup.config.js

@@ -1,3 +1,8 @@
+/*
+ * Copyright 2010-2020 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
 import typescript from 'rollup-plugin-typescript2';
 import nodeResolve from 'rollup-plugin-node-resolve';
 import commonjs from 'rollup-plugin-commonjs';
@@ -47,6 +52,13 @@ export default [
             format: 'cjs'
         }
     },
+    {
+        input: './tc-log-appender.js',
+        output: {
+            file: 'lib/tc-log-appender.js',
+            format: 'cjs'
+        }
+    },
     {
         input: './mocha-kotlin-reporter.js',
         external: ['path', 'util'],

libraries/tools/kotlin-test-js-runner/tc-log-appender.js

@@ -0,0 +1,26 @@
+/*
+ * Copyright 2010-2020 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+'use strict';
+
+import {tcEscape} from "./src/teamcity-format"
+
+const consoleLog = console.log.bind(console);
+
+function consoleAppender(layout, timezoneOffset) {
+    return (loggingEvent) => {
+        consoleLog(tcEscape(layout(loggingEvent, timezoneOffset)));
+    };
+}
+
+function configure(config, layouts) {
+    let layout = layouts.colouredLayout;
+    if (config.layout) {
+        layout = layouts.layout(config.layout.type, config.layout);
+    }
+    return consoleAppender(layout, config.timezoneOffset);
+}
+
+module.exports.configure = configure;