🔍 test: Check errors are instanceof Error.

Author: make-github-pseudonymous-again

test/src/error.js

@@ -21,6 +21,8 @@ function macro ( t , MyCodecError ) {
 
 	t.truthy( myerror ) ;
 
+	t.true( myerror instanceof Error ) ;
+
 	t.true( myerror instanceof ValueError ) ;
 
 	t.true( myerror instanceof CodecError ) ;