Add a dedicated CI workflow for data loader CLI

.github/workflows/data-loader-ci.yaml

@@ -0,0 +1,26 @@
+name: CI for Data Loader CLI
+
+on:
+  pull_request:
+  workflow_dispatch:
+
+jobs:
+  data_loader_ci:
+    name: Build Data Loader CLI
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up JDK 8
+        uses: actions/setup-java@v4
+        with:
+          distribution: 'temurin'
+          java-version: 8
+
+      - name: Setup Gradle
+        uses: gradle/actions/setup-gradle@v4
+
+      - name: Gradle Data Loader CLI build
+        run: ./gradlew :data-loader:cli:build --no-daemon --stacktrace
+

data-loader/cli/src/test/java/com/scalar/db/dataloader/cli/util/DirectoryUtilsTest.java

@@ -8,8 +8,12 @@
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
+import java.nio.file.attribute.PosixFilePermission;
+import java.util.HashSet;
+import java.util.Set;
 import java.util.stream.Stream;
 import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.Assumptions;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.io.TempDir;
 import org.slf4j.Logger;
@@ -44,13 +48,25 @@ void validateOrCreateTargetDirectory_DirectoryDoesNotExist_CreatesDirectory()
   @Test
   void validateOrCreateTargetDirectory_DirectoryNotWritable_ThrowsException() throws IOException {
     Path readOnlyDirectory = Files.createDirectory(Paths.get(tempDir.toString(), "readOnlyDir"));
-    readOnlyDirectory.toFile().setWritable(false);
 
+    // Try to make it read-only using POSIX if supported
+    try {
+      Set<PosixFilePermission> perms = new HashSet<>();
+      perms.add(PosixFilePermission.OWNER_READ);
+      perms.add(PosixFilePermission.OWNER_EXECUTE);
+      Files.setPosixFilePermissions(readOnlyDirectory, perms);
+    } catch (UnsupportedOperationException | IOException e) {
+      // Fall back for systems without POSIX support
+      readOnlyDirectory.toFile().setWritable(false);
+    }
+    // Verify it is actually non-writable
+    boolean isWritable = Files.isWritable(readOnlyDirectory);
+    Assumptions.assumeFalse(isWritable, "Directory is still writable; skipping test.");
+
+    // Test
     assertThrows(
         DirectoryValidationException.class,
-        () -> {
-          DirectoryUtils.validateOrCreateTargetDirectory(readOnlyDirectory.toString());
-        });
+        () -> DirectoryUtils.validateOrCreateTargetDirectory(readOnlyDirectory.toString()));
   }
 
   @Test