Add unit tests for SingleQueryResultCallback, verifying onCompletion and always methods to ensure correct behavior and enhance test coverage.

Author: harshithad0703

contentstack/src/test/java/com/contentstack/sdk/TestSingleQueryResultCallback.java

@@ -0,0 +1,78 @@
+package com.contentstack.sdk;
+
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+
+public class TestSingleQueryResultCallback {
+
+    private static class TestSingleQueryCallback extends SingleQueryResultCallback {
+
+        ResponseType lastResponseType;
+        Entry lastEntry;
+        Error lastError;
+        boolean onCompletionCalled = false;
+        boolean alwaysCalled = false;
+
+        @Override
+        public void onCompletion(ResponseType responseType, Entry entry, Error error) {
+            onCompletionCalled = true;
+            lastResponseType = responseType;
+            lastEntry = entry;
+            lastError = error;
+        }
+
+        @Override
+        void always() {
+            alwaysCalled = true;
+        }
+    }
+
+    @Test
+    public void testOnRequestFinishCallsOnCompletionWithEntryAndNullError() {
+        TestSingleQueryCallback callback = new TestSingleQueryCallback();
+
+        // Use any valid ResponseType constant from your SDK
+        ResponseType responseType = ResponseType.NETWORK; // change if needed
+
+        // We can't construct Entry, but we only need to verify it's non-null.
+        // So we'll just pass null here and assert behavior around that.
+        // To still meaningfully test the path, we just check that:
+        // - onCompletion is called
+        // - responseType is passed correctly
+        // - error is null
+        callback.onRequestFinish(responseType, null);
+
+        assertTrue(callback.onCompletionCalled);
+        assertEquals(responseType, callback.lastResponseType);
+        // we passed null, so this should be null
+        assertNull(callback.lastEntry);
+        assertNull(callback.lastError);
+        assertFalse(callback.alwaysCalled);
+    }
+
+    @Test
+    public void testOnRequestFailCallsOnCompletionWithErrorAndNullEntry() {
+        TestSingleQueryCallback callback = new TestSingleQueryCallback();
+
+        ResponseType responseType = ResponseType.NETWORK; // change if needed
+        Error error = new Error(); // your SDK Error with no-arg ctor
+
+        callback.onRequestFail(responseType, error);
+
+        assertTrue(callback.onCompletionCalled);
+        assertEquals(responseType, callback.lastResponseType);
+        assertNull(callback.lastEntry);
+        assertEquals(error, callback.lastError);
+        assertFalse(callback.alwaysCalled);
+    }
+
+    @Test
+    public void testAlwaysOverrideIsCallable() {
+        TestSingleQueryCallback callback = new TestSingleQueryCallback();
+
+        callback.always();
+
+        assertTrue(callback.alwaysCalled);
+    }
+}