diff --git a/test/commands/shell.js b/test/commands/shell.js
index 24de425..751ccad 100644
--- a/test/commands/shell.js
+++ b/test/commands/shell.js
@@ -40,8 +40,9 @@ describe('Shell command', function() {
 		shellCommand.run({cmd: 'echo1 "Hello world"'}, function(err) {
 			expect(err).ok();
 			expect(err).an(Error);
-			expect(err.message).contain('echo1:');
-			expect(err.message).contain('not found');
+			// messages are slightly different across the OSes
+			// e.g. at linux and macos
+			expect(err.message).match(/echo1:.*not found/);
 			expect(std.err).equal('');
 			expect(std.out).equal('');
 			done();