imp(Errors): writes errors to stderr

Closes #154

Cargo.toml

@@ -20,6 +20,9 @@ color = ["ansi_term"]
 # for building with nightly and unstable features
 unstable=[]
 
+# for building with debug messages
+debug=[]
+
 [dependencies.strsim]
 version = "0.4.0"
 optional = true

clap-tests/run_tests.py

@@ -298,9 +298,15 @@ def pass_fail(name, check, good):
 
 def main():
 	for cmd, cmd_v in cmds.items():
-		proc = subprocess.Popen(cmd_v[0], shell=True, stdout=subprocess.PIPE, universal_newlines=True)
-		out = _ansi.sub('', proc.communicate()[0].strip())
-		pass_fail(cmd, out, cmd_v[1])
+		proc = subprocess.Popen(cmd_v[0], shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE, universal_newlines=True)
+		out, err = proc.communicate()
+		out = _ansi.sub('', out.strip())
+		err = _ansi.sub('', err.strip())
+		if out:
+			pass_fail(cmd, out, cmd_v[1])
+		else:
+			pass_fail(cmd, err, cmd_v[1])
+
 	if failed:
 		print('One or more tests failed')
 		return 1