Simplify the install and uninstall commands and improve tests.

pre_commit/commands.py

@@ -0,0 +1,25 @@
+
+import os
+import pkg_resources
+import stat
+
+
+def install(runner):
+    """Install the pre-commit hooks."""
+    pre_commit_file = pkg_resources.resource_filename('pre_commit', 'resources/pre-commit.sh')
+    with open(runner.pre_commit_path, 'w') as pre_commit_file_obj:
+        pre_commit_file_obj.write(open(pre_commit_file).read())
+
+    original_mode = os.stat(runner.pre_commit_path).st_mode
+    os.chmod(
+        runner.pre_commit_path,
+        original_mode | stat.S_IXUSR | stat.S_IXGRP | stat.S_IXOTH,
+    )
+    return 0
+
+
+def uninstall(runner):
+    """Uninstall the pre-commit hooks."""
+    if os.path.exists(runner.pre_commit_path):
+        os.remove(runner.pre_commit_path)
+    return 0