utils.genio: Refactor is_patch_in_file function and add tests

Signed-off-by: NCaio Carrara <ccarrara@redhat.com>

avocado/utils/genio.py

@@ -203,21 +203,22 @@ def write_file_or_fail(filename, data):
                          filename, details))
 
 
-def find_pattern(filename,  pattern):
+def is_pattern_in_file(filename,  pattern):
     """
-    Module for match pattern in a specified file
+    Check if a pattern matches in a specified file. If a non
+    regular file be informed a GenIOError will be raised.
 
     :param filename: Path to file
     :type filename: str
-    :param pattern: pattern that need to match in file
+    :param pattern: Pattern that need to match in file
     :type pattern: str
     :return: True when pattern matches in file if not
-             retun False
+             return False
+    :rtype: boolean
     """
     if not os.path.isfile(filename):
         raise GenIOError('invalid file %s to match pattern %s'
                          % (filename, pattern))
-
     with open(filename, 'r') as content_file:
         if re.search(pattern, content_file.read(), re.MULTILINE):
             return True

selftests/unit/test_utils_genio.py

+import os
+import tempfile
+import unittest
+
+from avocado.utils import genio
+
+
+class TestGenio(unittest.TestCase):
+    def test_check_pattern_in_directory(self):
+        tempdirname = tempfile.mkdtemp()
+        with self.assertRaises(genio.GenIOError):
+            genio.is_pattern_in_file(tempdirname, 'something')
+        os.rmdir(tempdirname)
+
+    def test_check_simple_pattern_in_file_successfully(self):
+        with tempfile.NamedTemporaryFile(mode='w') as temp_file:
+            temp_file.write('Hello World')
+            temp_file.seek(0)
+            self.assertTrue(genio.is_pattern_in_file(temp_file.name, 'Hello'))
+
+    def test_check_pattern_in_file_successfully(self):
+        with tempfile.NamedTemporaryFile(mode='w') as temp_file:
+            temp_file.write('123')
+            temp_file.seek(0)
+            self.assertTrue(genio.is_pattern_in_file(temp_file.name, r'\d{3}'))
+
+    def test_check_pattern_in_file_unsuccessfully(self):
+        with tempfile.NamedTemporaryFile(mode='w') as temp_file:
+            temp_file.write('123')
+            temp_file.seek(0)
+            self.assertFalse(genio.is_pattern_in_file(temp_file.name, r'\D{3}'))