Move cat method to cmdtestlib

3 files changed, 35 insertions, 10 deletions

diff --git a/cmdtest b/cmdtest
index 42927e3..02cffcf 100755
--- a/cmdtest
+++ b/cmdtest
@@ -190,7 +190,8 @@ class CommandTester(cliapp.Application):
         if stderr_diff:
             errors.append(TestFailure(test, 'stderr diff:\n%s' % stderr_diff))
 
-        expected_exit = int(self.cat(test.exit or '/dev/null').strip() or '0')
+        contents = cmdtestlib.cat(test.exit or '/dev/null')
+        expected_exit = int(contents.strip() or '0')
         if exit != expected_exit:
             errors.append(TestFailure(test, 
                                       'got exit code %s, expected %s' %
@@ -204,15 +205,8 @@ class CommandTester(cliapp.Application):
         
         return errors
 
-    def cat(self, filename):
-        if os.path.exists(filename):
-            with open(filename) as f:
-                return f.read()
-        else:
-            return ''
-
     def lines(self, filename):
-        return self.cat(filename).splitlines()
+        return cmdtestlib.cat(filename).splitlines()
 
     def expand(self, strings):
         variables = {
diff --git a/cmdtestlib.py b/cmdtestlib.py
index 59a3879..460ab16 100644
--- a/cmdtestlib.py
+++ b/cmdtestlib.py
@@ -20,6 +20,15 @@ __version__ = '0.3'
 import os
 
 
+def cat(filename):
+    '''Return contents of file, or empty string if it doesn't exist.'''
+    if os.path.exists(filename):
+        with open(filename) as f:
+            return f.read()
+    else:
+        return ''
+
+
 class TestCase(object):
 
     def __init__(self, name, path_prefix):
diff --git a/cmdtestlib_tests.py b/cmdtestlib_tests.py
index a49cdad..52c72cd 100644
--- a/cmdtestlib_tests.py
+++ b/cmdtestlib_tests.py
@@ -14,9 +14,12 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 
+import os
+import shutil
+import tempfile
 import unittest
 
-from cmdtestlib import TestDir
+from cmdtestlib import TestDir, cat
 
 
 class TestDirTests(unittest.TestCase):
@@ -62,3 +65,22 @@ class TestDirTests(unittest.TestCase):
         self.assertEqual(td.find_prefixes(['setup', 'foo.setup', 'bar.script']), 
                          ['bar', 'foo'])
 
+
+class CatTests(unittest.TestCase):
+
+    def setUp(self):
+        self.tempdir = tempfile.mkdtemp()
+        
+    def tearDown(self):
+        shutil.rmtree(self.tempdir)
+        
+    def test_returns_empty_string_for_nonexistent_file(self):
+        filename = os.path.join(self.tempdir, 'file.txt')
+        self.assertEqual(cat(filename), '')
+        
+    def test_returns_contents_of_file(self):
+        filename = os.path.join(self.tempdir, 'file.txt')
+        with open(filename, 'w') as f:
+            f.write('foobar')
+        self.assertEqual(cat(filename), 'foobar')
+