Add rudimentary logging logic for the test-runner

Author: Gedochao

modules/test-runner/src/main/scala/scala/build/testrunner/DynamicTestRunner.scala

@@ -1,6 +1,6 @@
 package scala.build.testrunner
 
-import sbt.testing._
+import sbt.testing.{Logger => SbtTestLogger, _}
 
 import java.lang.annotation.Annotation
 import java.lang.reflect.Modifier
@@ -214,6 +214,8 @@ object DynamicTestRunner {
       parse(None, Nil, false, 0, None, args.toList)
     }
 
+    val logger = Logger(verbosity)
+
     val classLoader = Thread.currentThread().getContextClassLoader
     val classPath0  = TestRunner.classPath(classLoader)
     val frameworks = testFrameworkOpt
@@ -239,25 +241,25 @@ object DynamicTestRunner {
           s"${f.name()} (${Option(f.getClass.getCanonicalName).getOrElse(f.toString)})"
 
         val foundFrameworkServices = findFrameworkServices(classLoader)
-        if (verbosity >= 2 && foundFrameworkServices.nonEmpty)
-          System.err.println(
+        if (foundFrameworkServices.nonEmpty)
+          logger.debug(
             s"""Found test framework services:
                |  - ${foundFrameworkServices.map(getFrameworkDescription).mkString("\n  - ")}
                |""".stripMargin
           )
 
         val foundFrameworks =
           findFrameworks(classPath0, classLoader, TestRunner.commonTestFrameworks)
-        if (verbosity >= 2 && foundFrameworks.nonEmpty)
-          System.err.println(
+        if (foundFrameworks.nonEmpty)
+          logger.debug(
             s"""Found test frameworks:
                |  - ${foundFrameworks.map(getFrameworkDescription).mkString("\n  - ")}
                |""".stripMargin
           )
 
         val distinctFrameworks = distinctBy(foundFrameworkServices ++ foundFrameworks)(_.name())
-        if (verbosity >= 2 && distinctFrameworks.nonEmpty)
-          System.err.println(
+        if (distinctFrameworks.nonEmpty)
+          logger.debug(
             s"""Distinct test frameworks found (by framework name):
                |  - ${distinctFrameworks.map(getFrameworkDescription).mkString("\n  - ")}
                |""".stripMargin
@@ -272,16 +274,16 @@ object DynamicTestRunner {
                   f1.getClass.isAssignableFrom(f2.getClass)
                 )
             )
-        if (verbosity >= 1 && finalFrameworks.nonEmpty)
-          System.err.println(
+        if (finalFrameworks.nonEmpty)
+          logger.log(
             s"""Final list of test frameworks found:
                |  - ${finalFrameworks.map(getFrameworkDescription).mkString("\n  - ")}
                |""".stripMargin
           )
 
         val skippedInheritedFrameworks = distinctFrameworks.diff(finalFrameworks)
-        if (verbosity >= 1 && skippedInheritedFrameworks.nonEmpty)
-          System.err.println(
+        if (skippedInheritedFrameworks.nonEmpty)
+          logger.log(
             s"""The following test frameworks have been filtered out, as they're being inherited from by others:
                |  - ${skippedInheritedFrameworks.map(getFrameworkDescription).mkString("\n  - ")}
                |""".stripMargin
@@ -304,7 +306,7 @@ object DynamicTestRunner {
     val exitCodes =
       frameworks
         .map { framework =>
-          if (verbosity >= 1) System.err.println(s"Running test framework: ${framework.name}")
+          logger.log(s"Running test framework: ${framework.name}")
           val fingerprints = framework.fingerprints()
           val runner       = framework.runner(args0.toArray, Array(), classLoader)
 
@@ -336,15 +338,15 @@ object DynamicTestRunner {
           val doneMsg = runner.done()
           if (doneMsg.nonEmpty) out.println(doneMsg)
           if (requireTests && events.isEmpty) {
-            System.err.println(s"Error: no tests were run for ${framework.name()}.")
+            logger.error(s"Error: no tests were run for ${framework.name()}.")
             1
           }
           else if (failed) {
-            System.err.println(s"Error: ${framework.name()} tests failed.")
+            logger.error(s"Error: ${framework.name()} tests failed.")
             1
           }
           else {
-            if (verbosity >= 1) System.err.println(s"${framework.name()} tests ran successfully.")
+            logger.log(s"${framework.name()} tests ran successfully.")
             0
           }
         }

modules/test-runner/src/main/scala/scala/build/testrunner/Logger.scala

@@ -0,0 +1,21 @@
+package scala.build.testrunner
+
+import java.io.PrintStream
+
+class Logger(val verbosity: Int, out: PrintStream) {
+  def error(message: String): Unit = out.println(message)
+
+  def message(message: => String): Unit = if (verbosity >= 0) out.println(message)
+
+  def log(message: => String): Unit = if (verbosity >= 1) out.println(message)
+  def log(message: => String, debugMessage: => String): Unit =
+    if (verbosity >= 2) out.println(debugMessage)
+    else if (verbosity >= 1) out.println(message)
+
+  def debug(message: => String): Unit = if (verbosity >= 2) out.println(message)
+}
+
+object Logger {
+  def apply(verbosity: Int, out: PrintStream) = new Logger(verbosity, out)
+  def apply(verbosity: Int)                   = new Logger(verbosity, out = System.err)
+}

modules/test-runner/src/main/scala/scala/build/testrunner/TestRunner.scala

@@ -1,6 +1,6 @@
 package scala.build.testrunner
 
-import sbt.testing._
+import sbt.testing.{Logger => SbtTestLogger, _}
 
 import java.io.{File, PrintStream}
 import java.nio.file.{Path, Paths}
@@ -49,8 +49,8 @@ object TestRunner {
 
     val events = mutable.Buffer.empty[Event]
 
-    val logger: Logger =
-      new Logger {
+    val logger: SbtTestLogger =
+      new SbtTestLogger {
         def error(msg: String)   = out.println(msg)
         def warn(msg: String)    = out.println(msg)
         def info(msg: String)    = out.println(msg)