Fix exit codes

tests/shlaxfail.py

@@ -0,0 +1,18 @@
+#!/usr/bin/env python
+"""
+Shlaxfile for shlax itself.
+"""
+
+from shlax.shortcuts import *
+
+shlax = Container(
+    build=Buildah(
+        Packages('prout', upgrade=False),
+        base='alpine',
+        commit='shlaxfail',
+    ),
+)
+
+
+if __name__ == '__main__':
+    print(Group(doc=__doc__).load(shlax).entry_point())

tests/shlaxsuccess.py

@@ -0,0 +1,17 @@
+#!/usr/bin/env python
+"""
+Shlaxfile for shlax itself.
+"""
+
+from shlax.shortcuts import *
+
+shlax = Container(
+    build=Buildah(
+        base='alpine',
+        commit='shlaxsuccess',
+    ),
+)
+
+
+if __name__ == '__main__':
+    print(Group(doc=__doc__).load(shlax).entry_point())