Improve output of failed tests

Test group and test names are now displayed separately, an additional
line is added to show the location on which the test is defined, and all
output is now left aligned with the corresponding labels. This makes it
easier to read the output whenever there are test failures.

runtime/src/std/test/formatters.inko

 #! Built-in formatters for test suites.
 import std::ansi::(self, BOLD, CYAN, GREEN, RED)
 import std::conversion::ToString
+import std::debug::CallFrame
 import std::stdio::stdout
 import std::string_buffer::StringBuffer
 import std::test::error::TestFailure
@@ -33,15 +34,8 @@ object ProgressFormatter {
     @colors = colors
   }
-  ## Returns the title to use for a failed test.
-  def failure_title(test: Test) -> String {
-    StringBuffer.new(test.group_name, ' ', test.name).to_string
-  }
-
   ## Returns the location of a test failure.
-  def failure_location(failure: TestFailure) -> String {
-    let location = failure.location
-
+  def format_location(location: CallFrame) -> String {
     StringBuffer
       .new(location.path.to_string, ':', location.line.to_string)
       .to_string
@@ -128,18 +122,24 @@ impl Formatter for ProgressFormatter {
   def failures(tests: Array!(Test)) {
     stdout.write_string("\n\nFailures:")
-    tests.each do (test) {
+    tests.each_with_index do (test, index) {
       let failure = test.failure!
       let buffer = StringBuffer.new(
         "\n\n",
-        '  Test: ',
-        bold(failure_title(test)),
+        '  Group:            ',
+        test.group_name,
         "\n",
-        '  Location: ',
-        cyan(failure_location(failure)),
-        "\n\n",
-        '  ',
+        '  Test:             ',
+        bold(test.name),
+        "\n",
+        '  Test location:    ',
+        cyan(format_location(test.location)),
+        "\n",
+        '  Failure location: ',
+        cyan(format_location(failure.location)),
+        "\n",
+        '  Failure:          ',
         red(failure.message),
       )

runtime/tests/test/std/test/test_formatters.inko

@@ -19,21 +19,12 @@ def example_test -> Test {
   )
 }
-test.group('std::test::formatters::ProgressFormatter.failure_title') do (g) {
-  g.test('Generating the title for a failed test') {
-    let fmt = ProgressFormatter.new
-
-    assert.equal(fmt.failure_title(example_test), 'group name test name')
-  }
-}
-
-test.group('std::test::formatters::ProgressFormatter.failure_location') do (g) {
+test.group('std::test::formatters::ProgressFormatter.format_location') do (g) {
   g.test('Generating the failure location description for a failed test') {
     let fmt = ProgressFormatter.new
     let frame = CallFrame.new(path: 'test.inko', name: 'test', line: 1)
-    let failure = TestFailure.new(message: 'oops', location: frame)
-    assert.equal(fmt.failure_location(failure), 'test.inko:1')
+    assert.equal(fmt.format_location(frame), 'test.inko:1')
   }
 }