spring-test-slices: Spring Boot 4.1.2 test slices lab (@WebMvcTest, @JsonTest, @RestClientTest, @DataJpaTest vs @SpringBootTest)

Co-Authored-By: Claude Sonnet 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_017ic4b7Jbw5CxUQ13D7gn25

spring-test-slices/scripts/run-all.sh

@@ -0,0 +1,31 @@
+#!/usr/bin/env bash
+# Regenerates every file in spring-test-slices/output/.
+# Needs JDK 25 and Maven on the PATH. Takes about a minute.
+set -euo pipefail
+cd "$(dirname "$0")/.."
+
+OUT=output
+# keep transcripts free of JVM launcher noise that varies per machine
+filter() { grep -vE '^(Picked up JAVA_TOOL_OPTIONS|WARNING: )' || true; }
+
+rm -f "$OUT"/*.txt
+mkdir -p "$OUT"
+
+# 1. the whole suite: every test writes its own transcript to output/ and asserts the same facts
+mvn -B -q clean test 2>&1 | filter | grep -E 'Tests run:|BUILD|ERROR' || true
+
+# 2. which test jars does spring-boot-starter-test alone bring in?
+./scripts/starter-test-only.sh
+
+# 3. startup time of each context, one test class per JVM so nothing is cached.
+#    Spring Boot logs "Started <TestClass> in N seconds" for every context it builds.
+#    Timings vary by machine and by run: read them as indicative, not as a result.
+{
+  echo "Context startup time per test class (one class per mvn run; indicative, varies between runs)"
+  echo
+  for cls in JsonSliceTest RestClientSliceTest WebMvcSliceTest DataJpaSliceTest FullContextTest; do
+    mvn -B test -Dtest="$cls" 2>&1 | grep -oE "Started $cls in [0-9.]+ seconds" | head -1
+  done
+} > "$OUT/30-startup-times.txt"
+
+echo "done: $(ls "$OUT" | wc -l) files in $OUT/"