Introduce "minimal" test reporter (#1563)

pkl-core/src/test/kotlin/org/pkl/core/stdlib/MinimalReportTest.kt

@@ -0,0 +1,158 @@
+/*
+ * Copyright © 2026 Apple Inc. and the Pkl project authors. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.pkl.core.stdlib
+
+import java.io.StringWriter
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.Test
+import org.pkl.core.TestResults
+import org.pkl.core.TestResults.TestResult
+import org.pkl.core.TestResults.TestSectionResults
+import org.pkl.core.stdlib.test.report.MinimalReporter
+
+class MinimalReportTest {
+
+  @Test
+  fun `report with only passing tests does not show module or test names`() {
+    val resultsBuilder = TestResults.Builder("module1", "module1")
+    resultsBuilder.setFactsSection(
+      TestSectionResults(
+        TestResults.TestSectionName.FACTS,
+        listOf(TestResult("passing fact", 1, emptyList(), emptyList(), false)),
+      )
+    )
+    resultsBuilder.setExamplesSection(
+      TestSectionResults(
+        TestResults.TestSectionName.EXAMPLES,
+        listOf(TestResult("passing example", 1, emptyList(), emptyList(), false)),
+      )
+    )
+    val testResults = resultsBuilder.build()
+
+    val writer = StringWriter()
+    val minimalReport = MinimalReporter(false)
+    minimalReport.report(testResults, writer)
+
+    assertThat(writer.toString()).isEmpty()
+  }
+
+  @Test
+  fun `report with failures shows module name and only failed tests`() {
+    val resultsBuilder = TestResults.Builder("module1", "module1")
+    resultsBuilder.setFactsSection(
+      TestSectionResults(
+        TestResults.TestSectionName.FACTS,
+        listOf(
+          TestResult("passing fact", 1, emptyList(), emptyList(), false),
+          TestResult(
+            "failing fact",
+            1,
+            listOf(TestResults.Failure("Fact Failure", "failed")),
+            emptyList(),
+            false,
+          ),
+        ),
+      )
+    )
+    resultsBuilder.setExamplesSection(
+      TestSectionResults(
+        TestResults.TestSectionName.EXAMPLES,
+        listOf(TestResult("passing example", 1, emptyList(), emptyList(), false)),
+      )
+    )
+    val testResults = resultsBuilder.build()
+
+    val writer = StringWriter()
+    val minimalReport = MinimalReporter(false)
+    minimalReport.report(testResults, writer)
+
+    val output = writer.toString()
+    assertThat(output).contains("module module1")
+    assertThat(output).contains("failing fact")
+    assertThat(output).doesNotContain("passing fact")
+    assertThat(output).doesNotContain("passing example")
+    assertThat(output).doesNotContain("examples")
+  }
+
+  @Test
+  fun `summarize includes stats even when all tests pass`() {
+    val resultsBuilder = TestResults.Builder("module1", "module1")
+    resultsBuilder.setFactsSection(
+      TestSectionResults(
+        TestResults.TestSectionName.FACTS,
+        listOf(TestResult("passing fact", 1, emptyList(), emptyList(), false)),
+      )
+    )
+    resultsBuilder.setExamplesSection(
+      TestSectionResults(TestResults.TestSectionName.EXAMPLES, emptyList())
+    )
+    val testResults = listOf(resultsBuilder.build())
+
+    val writer = StringWriter()
+    val minimalReport = MinimalReporter(false)
+    minimalReport.summarize(testResults, writer)
+
+    val output = writer.toString()
+    assertThat(output).contains("100.0% tests pass")
+    assertThat(output).contains("1 passed")
+  }
+
+  @Test
+  fun `summarize method should generate correct output for failures`() {
+    val resultsBuilder = TestResults.Builder("module1", "module1")
+    resultsBuilder.setFactsSection(
+      TestSectionResults(
+        TestResults.TestSectionName.FACTS,
+        listOf(
+          TestResult(
+            "example1",
+            321919,
+            listOf(TestResults.Failure("Fact Failure", "failed")),
+            emptyList(),
+            false,
+          )
+        ),
+      )
+    )
+    resultsBuilder.setExamplesSection(
+      TestSectionResults(
+        TestResults.TestSectionName.EXAMPLES,
+        listOf(
+          TestResult(
+            "example1",
+            432525,
+            listOf(TestResults.Failure("Output Mismatch", "does not match")),
+            emptyList(),
+            false,
+          )
+        ),
+      )
+    )
+    val testResults = listOf(resultsBuilder.build())
+
+    val writer = StringWriter()
+    val minimalReport = MinimalReporter(false)
+    minimalReport.summarize(testResults, writer)
+
+    val expectedOutput =
+      """
+      0.0% tests pass [2/2 failed], 99.9% asserts pass [2/754444 failed]
+      """
+        .trimIndent()
+
+    assertThat(writer.toString().trimIndent()).isEqualTo(expectedOutput)
+  }
+}

pkl-core/src/test/kotlin/org/pkl/core/stdlib/SimpleReportTest.kt

@@ -16,19 +16,18 @@
 package org.pkl.core.stdlib
 
 import java.io.StringWriter
-import java.util.*
 import org.assertj.core.api.Assertions.assertThat
 import org.junit.jupiter.api.Test
 import org.pkl.core.TestResults
 import org.pkl.core.TestResults.TestResult
 import org.pkl.core.TestResults.TestSectionResults
-import org.pkl.core.stdlib.test.report.SimpleReport
+import org.pkl.core.stdlib.test.report.SpecReporter
 
 class SimpleReportTest {
 
   @Test
   fun `summarize method should generate correct output`() {
-    var resultsBuilder = TestResults.Builder("module1", "module1")
+    val resultsBuilder = TestResults.Builder("module1", "module1")
     resultsBuilder.setFactsSection(
       TestSectionResults(
         TestResults.TestSectionName.FACTS,
@@ -60,7 +59,7 @@ class SimpleReportTest {
     val testResults = listOf(resultsBuilder.build())
 
     val writer = StringWriter()
-    val simpleReport = SimpleReport(false)
+    val simpleReport = SpecReporter(false)
     simpleReport.summarize(testResults, writer)
 
     val expectedOutput =