Add strict meta schema validation test for block.json (#44423)

test/integration/blocks-schema.test.js

@@ -21,6 +21,16 @@ describe( 'block.json schema', () => {
 	] );
 	const ajv = new Ajv();
 
+	test( 'strictly adheres to the draft-04 meta schema', () => {
+		// Use ajv.compile instead of ajv.validateSchema to validate the schema
+		// because validateSchema only checks syntax, whereas, compile checks
+		// if the schema is semantically correct with strict mode.
+		// See https://github.com/ajv-validator/ajv/issues/1434#issuecomment-822982571
+		const result = ajv.compile( blockSchema );
+
+		expect( result.errors ).toBe( null );
+	} );
+
 	test( 'found block folders', () => {
 		expect( blockFolders.length ).toBeGreaterThan( 0 );
 	} );