First cut of chain tests

tests/test_chain.py

@@ -0,0 +1,18 @@
+import os
+
+from procs import Process
+
+
+TEST_DIR = os.path.abspath(os.path.join(
+    os.path.dirname(os.path.abspath(__file__)), 'test_data'
+))
+
+
+def test_chained_procs():
+    ls = Process('ls')
+    grep = Process('grep 2')
+    chain = ls | grep
+    chain.run()
+    assert chain.returncode == 0
+    assert chain.stdout == 'file2'
+