@@ -32,7 +32,7 @@ function webp_uploads_get_upload_image_mime_transforms() {
 	 *
 	 * @param array $default_transforms A map with the valid mime transforms.
 	 */
-	$transforms = (array) apply_filters( 'webp_uploads_upload_image_mime_transforms', $default_transforms );
+	$transforms = apply_filters( 'webp_uploads_upload_image_mime_transforms', $default_transforms );
 
 	// Return the default mime transforms if a non-array result is returned from the filter.
 	if ( ! is_array( $transforms ) ) {
 
@@ -335,4 +335,79 @@ function () {
 		$this->assertSame( 'image_additional_generated_error', $result->get_error_code() );
 	}
 
+	/**
+	 * Returns an empty array when the overwritten with empty array by webp_uploads_upload_image_mime_transforms filter.
+	 *
+	 * @test
+	 */
+	public function it_should_return_empty_array_when_filter_returns_empty_array() {
+		add_filter( 'webp_uploads_upload_image_mime_transforms', '__return_empty_array' );
+
+		$transforms = webp_uploads_get_upload_image_mime_transforms();
+
+		$this->assertIsArray( $transforms );
+		$this->assertSame( array(), $transforms );
+	}
+
+	/**
+	 * Returns default transforms when the overwritten with non array type by webp_uploads_upload_image_mime_transforms filter.
+	 *
+	 * @test
+	 */
+	public function it_should_return_default_transforms_when_filter_returns_non_array_type() {
+		add_filter(
+			'webp_uploads_upload_image_mime_transforms',
+			function () {
+				return;
+			}
+		);
+
+		$default_transforms = array(
+			'image/jpeg' => array( 'image/jpeg', 'image/webp' ),
+			'image/webp' => array( 'image/webp', 'image/jpeg' ),
+		);
+
+		$transforms = webp_uploads_get_upload_image_mime_transforms();
+
+		$this->assertIsArray( $transforms );
+		$this->assertSame( $default_transforms, $transforms );
+	}
+
+	/**
+	 * Returns transforms array with fallback to original mime with invalid transforms array.
+	 *
+	 * @test
+	 */
+	public function it_should_return_fallback_transforms_when_overwritten_invalid_transforms() {
+		add_filter(
+			'webp_uploads_upload_image_mime_transforms',
+			function () {
+				return array( 'image/jpeg' => array() );
+			}
+		);
+
+		$transforms = webp_uploads_get_upload_image_mime_transforms();
+
+		$this->assertIsArray( $transforms );
+		$this->assertSame( array( 'image/jpeg' => array( 'image/jpeg' ) ), $transforms );
+	}
+
+	/**
+	 * Returns custom transforms array when overwritten by webp_uploads_upload_image_mime_transforms filter.
+	 *
+	 * @test
+	 */
+	public function it_should_return_custom_transforms_when_overwritten_by_filter() {
+		add_filter(
+			'webp_uploads_upload_image_mime_transforms',
+			function () {
+				return array( 'image/jpeg' => array( 'image/jpeg', 'image/webp' ) );
+			}
+		);
+
+		$transforms = webp_uploads_get_upload_image_mime_transforms();
+
+		$this->assertIsArray( $transforms );
+		$this->assertSame( array( 'image/jpeg' => array( 'image/jpeg', 'image/webp' ) ), $transforms );
+	}
 }
Original file line number	Diff line number	Diff line change
`@@ -32,7 +32,7 @@ function webp_uploads_get_upload_image_mime_transforms() {`
`32`	`32`	`*`
`33`	`33`	`* @param array $default_transforms A map with the valid mime transforms.`
`34`	`34`	`*/`
`35`		`- $transforms = (array) apply_filters( 'webp_uploads_upload_image_mime_transforms', $default_transforms );`
	`35`	`+ $transforms = apply_filters( 'webp_uploads_upload_image_mime_transforms', $default_transforms );`
`36`	`36`
`37`	`37`	`// Return the default mime transforms if a non-array result is returned from the filter.`
`38`	`38`	`if ( ! is_array( $transforms ) ) {`