JPS, tests: Add docs for incremental/cacheVersionChanged tests

Original commit: 06b908d48f

jps/jps-plugin/jps-tests/test/org/jetbrains/kotlin/jps/build/AbstractDataContainerVersionChangedTest.kt

@@ -19,6 +19,9 @@ package org.jetbrains.kotlin.jps.build
 import org.jetbrains.kotlin.incremental.testingUtils.BuildLogFinder
 import org.jetbrains.kotlin.jps.targets.KotlinModuleBuildTarget
 
+/**
+ * @see [jps-plugin/testData/incremental/cacheVersionChanged/README.md]
+ */
 abstract class AbstractDataContainerVersionChangedTest : AbstractIncrementalCacheVersionChangedTest() {
     override val buildLogFinder: BuildLogFinder
         get() = BuildLogFinder(isDataContainerBuildLogEnabled = true)

jps/jps-plugin/jps-tests/test/org/jetbrains/kotlin/jps/build/AbstractIncrementalCacheVersionChangedTest.kt

@@ -21,6 +21,9 @@ import org.jetbrains.kotlin.incremental.testingUtils.ModifyContent
 import org.jetbrains.kotlin.jps.incremental.CacheVersionManager
 import org.jetbrains.kotlin.jps.targets.KotlinModuleBuildTarget
 
+/**
+ * @see [jps-plugin/testData/incremental/cacheVersionChanged/README.md]
+ */
 abstract class AbstractIncrementalCacheVersionChangedTest : AbstractIncrementalJpsTest(allowNoFilesWithSuffixInTestData = true) {
     override fun performAdditionalModifications(modifications: List<Modification>) {
         val modifiedFiles = modifications.filterIsInstance<ModifyContent>().map { it.path }

jps/jps-plugin/testData/incremental/cacheVersionChanged/README.md

@@ -0,0 +1,16 @@
+The same tests are run by both `AbstractIncrementalCacheVersionChangedTest` and `AbstractDataContainerVersionChangedTest`.
+
+## AbstractIncrementalCacheVersionChangedTest
+
+Tests for changing targets **local** cache version for each modification step.
+
+Individual tests can:
+- can skip changing the version at any step by adding files like `module1_do-not-change-cache-versions.new.2`
+- clear has-kotlin flag by adding files like `module1_clear-has-kotlin.new.1`
+
+## AbstractDataContainerVersionChangedTest
+
+Tests for changing version of **global** lookups cache for each modification step.
+Note that `build.log` file for this test case is named as `data-container-version-build.log`.
+
+Individual tests can can skip changing the version at any step by adding files like `module1_do-not-change-cache-versions.new.2`.