Avoid removing target/classes dir during IC in Maven

#KT-21581 fixed

libraries/tools/kotlin-maven-plugin-test/src/test/java/org.jetbrains.kotlin.maven/IncrementalCompilationIT.java

@@ -9,7 +9,8 @@ public class IncrementalCompilationIT extends MavenITBase {
         MavenProject project = new MavenProject("kotlinSimple");
         project.exec("package")
                .succeeded()
-               .compiledKotlin("src/A.kt", "src/useA.kt", "src/Dummy.kt");
+               .fileExists("target/classes/test.properties")
+               .compiledKotlin("src/main/kotlin/A.kt", "src/main/kotlin/useA.kt", "src/main/kotlin/Dummy.kt");
     }
 
     @Test
@@ -27,7 +28,7 @@ public class IncrementalCompilationIT extends MavenITBase {
         MavenProject project = new MavenProject("kotlinSimple");
         project.exec("package");
 
-        File aKt = project.file("src/A.kt");
+        File aKt = project.file("src/main/kotlin/A.kt");
         String original = "class A";
         String replacement = "private class A";
         MavenTestUtils.replaceFirstInFile(aKt, original, replacement);
@@ -39,7 +40,7 @@ public class IncrementalCompilationIT extends MavenITBase {
         MavenTestUtils.replaceFirstInFile(aKt, replacement, original);
         project.exec("package")
                .succeeded()
-               .compiledKotlin("src/A.kt", "src/useA.kt");
+               .compiledKotlin("src/main/kotlin/A.kt", "src/main/kotlin/useA.kt");
 
     }
 
@@ -48,12 +49,12 @@ public class IncrementalCompilationIT extends MavenITBase {
         MavenProject project = new MavenProject("kotlinSimple");
         project.exec("package");
 
-        File aKt = project.file("src/A.kt");
+        File aKt = project.file("src/main/kotlin/A.kt");
         MavenTestUtils.replaceFirstInFile(aKt, "fun foo", "internal fun foo");
 
         project.exec("package")
                .succeeded()
-               .compiledKotlin("src/A.kt", "src/useA.kt");
+               .compiledKotlin("src/main/kotlin/A.kt", "src/main/kotlin/useA.kt");
 
         // todo rebuild and compare output
     }

libraries/tools/kotlin-maven-plugin-test/src/test/java/org.jetbrains.kotlin.maven/MavenExecutionResult.java

@@ -110,4 +110,14 @@ class MavenExecutionResult {
             }
         });
     }
+
+    MavenExecutionResult fileExists(@NotNull final String path) throws Exception {
+        return check(new Action<MavenExecutionResult>() {
+            @Override
+            public void run(MavenExecutionResult execResult) {
+                File file = new File(workingDir, path);
+                Assert.assertTrue(file + " does not exist", file.exists());
+            }
+        });
+    }
 }

libraries/tools/kotlin-maven-plugin-test/src/test/resources/kotlinSimple/pom.xml

@@ -21,6 +21,8 @@
     </dependencies>
 
     <build>
+        <sourceDirectory>${project.basedir}/src/main/kotlin</sourceDirectory>
+
         <pluginManagement>
             <plugins>
                 <plugin>
@@ -40,7 +42,6 @@
             </plugins>
         </pluginManagement>
 
-        <sourceDirectory>${project.basedir}/src</sourceDirectory>
         <plugins>
             <plugin>
                 <artifactId>kotlin-maven-plugin</artifactId>

libraries/tools/kotlin-maven-plugin-test/src/test/resources/kotlinSimple/src/main/resources/test.properties

@@ -0,0 +1 @@
+example.property=101