Add a no commit to specific branch hook. (#185)

* add no commit code and config

* add the code

* remove version tweak

* fix logic, remove newline

* add Tests and cleanup testing issues

* remove extraneous modules

* cleanup some pep8 and flake issues

* reorder imports

* more fixes for syntax checking

* code cleanup based off asottile comments

* Use Contractions Properly, alphabatize new hook.

* Adding support for branches with a slash in them.

tests/check_no_commit_to_branch_test.py

@@ -0,0 +1,47 @@
+from __future__ import absolute_import
+from __future__ import unicode_literals
+
+from pre_commit_hooks.no_commit_to_branch import is_on_branch
+from pre_commit_hooks.no_commit_to_branch import main
+from pre_commit_hooks.util import cmd_output
+
+
+def test_other_branch(temp_git_dir):
+    with temp_git_dir.as_cwd():
+        cmd_output('git', 'checkout', '-b', 'anotherbranch')
+        assert is_on_branch('master') is False
+
+
+def test_multi_branch(temp_git_dir):
+    with temp_git_dir.as_cwd():
+        cmd_output('git', 'checkout', '-b', 'another/branch')
+        assert is_on_branch('master') is False
+
+
+def test_multi_branch_fail(temp_git_dir):
+    with temp_git_dir.as_cwd():
+        cmd_output('git', 'checkout', '-b', 'another/branch')
+        assert is_on_branch('another/branch') is True
+
+
+def test_master_branch(temp_git_dir):
+    with temp_git_dir.as_cwd():
+        assert is_on_branch('master') is True
+
+
+def test_main_b_call(temp_git_dir):
+    with temp_git_dir.as_cwd():
+        cmd_output('git', 'checkout', '-b', 'other')
+        assert main(['-b', 'other']) == 1
+
+
+def test_main_branch_call(temp_git_dir):
+    with temp_git_dir.as_cwd():
+        cmd_output('git', 'checkout', '-b', 'other')
+        assert main(['--branch', 'other']) == 1
+
+
+def test_main_default_call(temp_git_dir):
+    with temp_git_dir.as_cwd():
+        cmd_output('git', 'checkout', '-b', 'anotherbranch')
+        assert main() == 0