auto set -ea for #1322

pitest-entry/src/main/java/org/pitest/mutationtest/autoconfig/EnableAssertions.java

@@ -0,0 +1,34 @@
+package org.pitest.mutationtest.autoconfig;
+
+import org.pitest.mutationtest.config.ConfigurationUpdater;
+import org.pitest.mutationtest.config.ReportOptions;
+import org.pitest.plugin.Feature;
+import org.pitest.plugin.FeatureSetting;
+
+import static java.util.Collections.singletonList;
+
+/**
+ * Gradle and maven both now automatically set the -ea flag to
+ * enable assertions when running tests. Pitest must therefore
+ * do it too.
+ */
+public class EnableAssertions implements ConfigurationUpdater {
+
+    @Override
+    public void updateConfig(FeatureSetting conf, ReportOptions toModify) {
+        toModify.addChildJVMArgs(singletonList("-ea"));
+    }
+
+    @Override
+    public Feature provides() {
+        return Feature.named("AUTO_ASSERTIONS")
+                .withOnByDefault(true)
+                .withDescription(description());
+    }
+
+    @Override
+    public String description() {
+        return "Automatically add -ea to launch args to enable assertions";
+    }
+
+}

pitest-entry/src/main/resources/META-INF/services/org.pitest.mutationtest.config.ConfigurationUpdater

@@ -1,2 +1,3 @@
 org.pitest.mutationtest.autoconfig.KeepMacOsFocus
-org.pitest.mutationtest.autoconfig.AutoSetThreads
+org.pitest.mutationtest.autoconfig.AutoSetThreads
+org.pitest.mutationtest.autoconfig.EnableAssertions

pitest-entry/src/test/java/org/pitest/mutationtest/autoconfig/EnableAssertionsTest.java

@@ -0,0 +1,28 @@
+package org.pitest.mutationtest.autoconfig;
+
+import org.junit.Test;
+import org.pitest.mutationtest.config.ReportOptions;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class EnableAssertionsTest {
+    EnableAssertions underTest = new EnableAssertions();
+
+    @Test
+    public void addsEAFlag() {
+        ReportOptions data = new ReportOptions();
+
+        underTest.updateConfig(null, data);
+        assertThat(data.getJvmArgs()).contains("-ea");
+    }
+
+    @Test
+    public void featureIsNamedAutoAssertions() {
+        assertThat(underTest.provides().name()).isEqualTo("auto_assertions");
+    }
+
+    @Test
+    public void featureIsOnByDefault() {
+        assertThat(underTest.provides().isOnByDefault()).isTrue();
+    }
+}