From c57653dd5bff8e7ad3d2863e63476cc1c3a43ab3 Mon Sep 17 00:00:00 2001
From: Stephan Schroevers <stephan.schroevers@teampicnic.com>
Date: Tue, 9 Aug 2022 14:38:19 +0200
Subject: [PATCH] Introduce `run-mutation-tests.sh` (#170)

This script executes Pitest to determine the code base' mutation test coverage.
The set of tests executed can optionally be restricted by name. The results are
found in each Maven module's `target/pit-reports` directory.
---
 pom.xml               |  8 ++++++--
 run-mutation-tests.sh | 21 +++++++++++++++++++++
 2 files changed, 27 insertions(+), 2 deletions(-)
 create mode 100755 run-mutation-tests.sh

diff --git a/pom.xml b/pom.xml
index 7ed1c987..cdc945db 100644
--- a/pom.xml
+++ b/pom.xml
@@ -73,7 +73,8 @@
         this 'argLine' property instead of the definition of the 'argLine'
         configuration setting allows users or plugins to specify additional
         arguments. In particular, JaCoCo relies on this for the configuration
-        of its Java agent. -->
+        of its Java agent, and Pitest uses this configuration when it spawns
+        additional JVMs. -->
         <argLine>
             <!-- The JVM arguments specified in `.mvn/jvm.config` also apply to
             test JVMs, as those are also non-interactive processess running
@@ -99,7 +100,7 @@
             <!-- We cap memory usage. This may be relevant for build agents,
             but also prevents excessive memory usage by heavily parallelized
             local builds. -->
-            -Xmx1024m
+            -Xmx${argLine.xmx}
             <!-- This argument cannot be set through Surefire's
             'systemPropertyVariables' configuration setting. Setting the file
             encoding is necessary because forked unit test invocations
@@ -118,6 +119,9 @@
             from showing up in the dock and capturing window focus. -->
             -Djava.awt.headless=true
         </argLine>
+        <!-- The maximum amount of heap memory available to forked Surefire
+        processes. Factored out into a separate property to allow overriding. -->
+        <argLine.xmx>1024m</argLine.xmx>
         <!-- Our build system provides a monotonically increasing build number.
         When building locally, this number is obviously absent. So we provide a
         default value. -->
diff --git a/run-mutation-tests.sh b/run-mutation-tests.sh
new file mode 100755
index 00000000..66826c14
--- /dev/null
+++ b/run-mutation-tests.sh
@@ -0,0 +1,21 @@
+#!/usr/bin/env bash
+
+# Executes Pitest to determine the code base' mutation test coverage. The set
+# of tests executed can optionally be restricted by name. The results are found
+# in each Maven module's `target/pit-reports` directory.
+
+set -e -u -o pipefail
+
+if [ "${#}" -gt 1 ]; then
+  echo "Usage: ./$(basename "${0}") [TargetTests]"
+  exit 1
+fi
+
+targetTests=${1:-*}
+
+mvn clean test pitest:mutationCoverage \
+  -DargLine.xmx=2048m \
+  -Dverification.skip \
+  -DfailIfNoTests=false \
+  -Dtest="${targetTests}" \
+  -DtargetTests="${targetTests}"