LightCodeInsightTestCase: now test name can force the language level.

java/testFramework/src/com/intellij/testFramework/LightCodeInsightTestCase.java

@@ -23,10 +23,15 @@ import com.intellij.pom.java.LanguageLevel;
 import com.intellij.psi.impl.JavaPsiFacadeEx;
 import org.jetbrains.annotations.NotNull;
 
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
 /**
  * A TestCase for single PsiFile being opened in Editor conversion. See configureXXX and checkResultXXX method docs.
  */
 public abstract class LightCodeInsightTestCase extends LightPlatformCodeInsightTestCase {
+  private static final Pattern JDK_SELECT_PATTERN = Pattern.compile("Java([\\d.]+).java$");
+
   public static JavaPsiFacadeEx getJavaFacade() {
     return JavaPsiFacadeEx.getInstanceEx(ourProject);
   }
@@ -37,7 +42,31 @@ public abstract class LightCodeInsightTestCase extends LightPlatformCodeInsightT
     setLanguageLevel(getLanguageLevel());
   }
 
+  /**
+   * Returns a language level for test. Could be overridden for specific behavior.
+   * <p>
+   * This implementation checks the test name. If it ends with JavaXYZ.java and
+   * XYZ is known Java version (e.g. Java1.4.java or Java9.java), then version XYZ is returned.
+   * Otherwise {@link #getDefaultLanguageLevel() default version} is returned.
+   *
+   * @return a project language level for test.
+   */
   protected LanguageLevel getLanguageLevel() {
+    Matcher matcher = JDK_SELECT_PATTERN.matcher(getTestName(false));
+    if(matcher.find()) {
+      LanguageLevel level = LanguageLevel.parse(matcher.group(1));
+      if (level != null) {
+        return level;
+      }
+    }
+
+    return getDefaultLanguageLevel();
+  }
+
+  /**
+   * @return default language level if it's not forced by test name
+   */
+  protected LanguageLevel getDefaultLanguageLevel() {
     return LanguageLevel.HIGHEST;
   }