Can't find init.sql script when run from IntelliJ

[lukaseder]

This error appears when running the PostgreSQL mcve from within IntelliJ:

org.testcontainers.containers.ContainerLaunchException: Container startup failed

	at org.testcontainers.containers.GenericContainer.doStart(GenericContainer.java:349)
	at org.testcontainers.containers.GenericContainer.start(GenericContainer.java:322)
	at org.jooq.mcve.test.java.postgres.JavaTest.init(JavaTest.java:42)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:568)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:59)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:56)
	at org.junit.internal.runners.statements.RunBefores.invokeMethod(RunBefores.java:33)
	at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:24)
	at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:27)
	at org.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:306)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:413)
	at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
	at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:69)
	at com.intellij.rt.junit.IdeaTestRunner$Repeater$1.execute(IdeaTestRunner.java:38)
	at com.intellij.rt.execution.junit.TestsRepeater.repeat(TestsRepeater.java:11)
	at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:35)
	at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:235)
	at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:54)
Caused by: org.rnorth.ducttape.RetryCountExceededException: Retry limit hit with exception
	at org.rnorth.ducttape.unreliables.Unreliables.retryUntilSuccess(Unreliables.java:88)
	at org.testcontainers.containers.GenericContainer.doStart(GenericContainer.java:334)
	... 21 more
Caused by: org.testcontainers.containers.ContainerLaunchException: Could not create/start container
	at org.testcontainers.containers.GenericContainer.tryStart(GenericContainer.java:542)
	at org.testcontainers.containers.GenericContainer.lambda$doStart$0(GenericContainer.java:344)
	at org.rnorth.ducttape.unreliables.Unreliables.retryUntilSuccess(Unreliables.java:81)
	... 22 more
Caused by: org.testcontainers.ext.ScriptUtils$ScriptLoadException: Could not load classpath init script: /db/migration/init.sql. Resource not found.
	at org.testcontainers.ext.ScriptUtils.runInitScript(ScriptUtils.java:357)
	at org.testcontainers.containers.JdbcDatabaseContainer.runInitScriptIfRequired(JdbcDatabaseContainer.java:323)
	at org.testcontainers.containers.JdbcDatabaseContainer.containerIsStarted(JdbcDatabaseContainer.java:188)
	at org.testcontainers.containers.GenericContainer.containerIsStarted(GenericContainer.java:701)
	at org.testcontainers.containers.GenericContainer.tryStart(GenericContainer.java:521)
	... 24 more

[lukaseder]

A call to:

System.out.println(JavaTest.class.getResource("/db/migration/init.sql"));

Yields:

file:/C:/Users/lukas/jOOQ/jOOQ-mcve/jOOQ-mcve-java-postgres/target/classes/db/migration/init.sql

Curiously, testcontainers tries loading the resource with ClassLoader::getResource instead of Class::getResource. There seems to be a difference in behaviour where the latter accepts paths with a leading / when the former doesn't.

[lukaseder]

This problem doesn't appear when the code is run from mvn test, because in that case, we're using the maven-configured testcontainers instance, and don't have to initialise one in the test.