Add unit tests

Author: ernilambar

tests/phpunit/testdata/plugins/test-plugin-i18n-usage-errors/load.php

@@ -34,3 +34,9 @@
 
 esc_html__( 'Hello World!', 'textdomain' ); // Restricted textdomain. Severity should be 7.
 esc_html__( 'Hello World!', 'woocommerce' ); // Severity should be default 5.
+
+// Non singular string literals.
+echo esc_html__( $test, 'test-plugin-i18n-usage-errors' );
+echo _n( $single, $plural, $number, 'test-plugin-i18n-usage-errors' );
+echo _n_noop( $single, $plural, 'test-plugin-i18n-usage-errors' );
+echo _x( $text, $context, 'test-plugin-i18n-usage-errors' );

tests/phpunit/tests/Checker/Checks/I18n_Usage_Check_Tests.php

@@ -39,6 +39,22 @@ public function test_run_with_errors() {
 		// Mismatched textdomain but not restricted and with severity 5.
 		$this->assertCount( 1, wp_list_filter( $errors['load.php'][36][29], array( 'code' => 'WordPress.WP.I18n.TextDomainMismatch' ) ) );
 		$this->assertSame( 5, $errors['load.php'][36][29][0]['severity'] );
+
+		// print_r( $errors );
+
+		// Non singular string literal errors.
+		$this->assertCount( 1, wp_list_filter( $errors['load.php'][40][10], array( 'code' => 'WordPress.WP.I18n.NonSingularStringLiteralSingle' ) ) );
+		$this->assertSame( 7, $errors['load.php'][40][10][0]['severity'] );
+		$this->assertCount( 1, wp_list_filter( $errors['load.php'][40][19], array( 'code' => 'WordPress.WP.I18n.NonSingularStringLiteralPlural' ) ) );
+		$this->assertSame( 7, $errors['load.php'][40][19][0]['severity'] );
+		$this->assertCount( 1, wp_list_filter( $errors['load.php'][41][15], array( 'code' => 'WordPress.WP.I18n.NonSingularStringLiteralSingular' ) ) );
+		$this->assertSame( 7, $errors['load.php'][41][15][0]['severity'] );
+		$this->assertCount( 1, wp_list_filter( $errors['load.php'][41][24], array( 'code' => 'WordPress.WP.I18n.NonSingularStringLiteralPlural' ) ) );
+		$this->assertSame( 7, $errors['load.php'][41][24][0]['severity'] );
+		$this->assertCount( 1, wp_list_filter( $errors['load.php'][42][10], array( 'code' => 'WordPress.WP.I18n.NonSingularStringLiteralText' ) ) );
+		$this->assertSame( 7, $errors['load.php'][42][10][0]['severity'] );
+		$this->assertCount( 1, wp_list_filter( $errors['load.php'][42][17], array( 'code' => 'WordPress.WP.I18n.NonSingularStringLiteralContext' ) ) );
+		$this->assertSame( 7, $errors['load.php'][42][17][0]['severity'] );
 	}
 
 	public function test_run_without_errors() {