Merge pull request #261 from olafurpg/escape-testname

Fix #258 - escape "non-visible" characters in test names.

munit/shared/src/main/scala/munit/MUnitRunner.scala

@@ -24,6 +24,7 @@ import scala.concurrent.Future
 import scala.concurrent.ExecutionContext
 import java.util.concurrent.ExecutionException
 import munit.internal.junitinterface.Settings
+import munit.internal.console.Printers
 
 class MUnitRunner(val cls: Class[_ <: Suite], newInstance: () => Suite)
     extends Runner
@@ -62,7 +63,7 @@ class MUnitRunner(val cls: Class[_ <: Suite], newInstance: () => Suite)
   def createTestDescription(test: suite.Test): Description = {
     descriptions.getOrElseUpdate(
       test, {
-        val escapedName = test.name.replace("\n", "\\n")
+        val escapedName = Printers.escapeNonVisible(test.name)
         val testName = munit.internal.Compat.LazyList
           .from(0)
           .map {

munit/shared/src/main/scala/munit/internal/console/Printers.scala

@@ -188,7 +188,39 @@ object Printers {
     }
   }
 
-  private def printChar(c: Char, sb: StringBuilder) =
+  /**
+   * Pretty-prints this string with non-visible characters escaped.
+   *
+   * The exact definition of "non-visible" is fuzzy and is subject to change.
+   * The original motivation for this method was to fix
+   * https://github.com/scalameta/munit/issues/258 related to escaping \r in
+   * test names.
+   *
+   * The spirit of this method is to preserve "visible" characters like emojis
+   * and double quotes and escape "non-visible" characters like newlines and
+   * ANSI escape codes. A non-goal of this method is to make the output
+   * copy-pasteable back into source code unlike the `printChar` method, which
+   * escapes for example double-quote characters.
+   */
+  def escapeNonVisible(string: String): String = {
+    val out = new StringBuilder()
+    var i = 0
+    while (i < string.length()) {
+      val ch = string.charAt(i)
+      (ch: @switch) match {
+        case '"' | '\'' => out.append(ch)
+        case _          => printChar(ch, out, isEscapeUnicode = false)
+      }
+      i += 1
+    }
+    out.toString()
+  }
+
+  private def printChar(
+      c: Char,
+      sb: StringBuilder,
+      isEscapeUnicode: Boolean = true
+  ): Unit =
     (c: @switch) match {
       case '"'  => sb.append("\\\"")
       case '\\' => sb.append("\\\\")
@@ -198,9 +230,9 @@ object Printers {
       case '\r' => sb.append("\\r")
       case '\t' => sb.append("\\t")
       case c =>
-        val isUnicode = false
-        if (c < ' ' || (c > '~' && isUnicode))
-          sb.append("\\u%04x" format c.toInt)
+        val isNonReadableAscii = c < ' ' || (c > '~' && isEscapeUnicode)
+        if (isNonReadableAscii && !Character.isLetter(c))
+          sb.append("\\u%04x".format(c.toInt))
         else sb.append(c)
     }
 

tests/shared/src/main/scala/munit/TestNameFrameworkSuite.scala

@@ -1,22 +1,30 @@
 package munit
 
 class TestNameFrameworkSuite extends FunSuite {
-  test("basic") {
-    // pass
-  }
-  test("basic") {
-    // pass
-  }
-  test("newline\n") {
-    // pass
-  }
+  test("basic") {}
+  test("basic") {}
+  test("newline\n") {}
+  test("carriage-return\r\n") {}
+  test("tab\t") {}
+  test("return\t") {}
+  test("form-feed\f") {}
+  test("substitute\u001az") {}
+  test("emoji😆") {}
+  test("red" + Console.RED) {}
 }
 
 object TestNameFrameworkSuite
     extends FrameworkTest(
       classOf[TestNameFrameworkSuite],
-      """|==> success munit.TestNameFrameworkSuite.basic
-         |==> success munit.TestNameFrameworkSuite.basic-1
-         |==> success munit.TestNameFrameworkSuite.newline\n
-         |""".stripMargin
+      s"""|==> success munit.TestNameFrameworkSuite.basic
+          |==> success munit.TestNameFrameworkSuite.basic-1
+          |==> success munit.TestNameFrameworkSuite.newline\\n
+          |==> success munit.TestNameFrameworkSuite.carriage-return\\r\\n
+          |==> success munit.TestNameFrameworkSuite.tab\\t
+          |==> success munit.TestNameFrameworkSuite.return\\t
+          |==> success munit.TestNameFrameworkSuite.form-feed\\f
+          |==> success munit.TestNameFrameworkSuite.substitute\\u001az
+          |==> success munit.TestNameFrameworkSuite.emoji😆
+          |==> success munit.TestNameFrameworkSuite.red\\u001b[31m
+          |""".stripMargin
     )