Large code refactoring

* Add tests
* Remove git dependency (only needed when a git identifier is specified)

tests/functional/test_cmd_line_call.py

@@ -0,0 +1,4 @@
+import unittest
+
+class CallLinterFromCommandLineTest(unittest.TestCase):
+    pass

tests/functional/test_migration_linter.py

@@ -66,19 +66,19 @@ class BackwardcompatibilityDetectionTest(unittest.TestCase):
         fixtures.prepare_git_project(test_project_path)
         self._test_linter_finds_no_errors(
             test_project_path,
-            commit_id='44330921696018f8f1480df897b38310549982cb')
+            commit_id='1021d98b5943db56122c1f848f371ddc38788d0f')
 
-    #def test_specify_git_hash_by_tag(self):
-    #    test_project_path = fixtures.MULTI_COMMIT_PROJECT
-    #    fixtures.prepare_git_project(test_project_path)
-    #    self._test_linter_finds_no_errors(test_project_path, commit_id='tag1')
+    def test_specify_git_hash_by_tag(self):
+        test_project_path = fixtures.MULTI_COMMIT_PROJECT
+        fixtures.prepare_git_project(test_project_path)
+        self._test_linter_finds_no_errors(test_project_path, commit_id='tag1')
 
     def _test_linter_finds_errors(self, path, commit_id=None):
-        linter = MigrationLinter(path, commit_id=commit_id)
-        has_errors = linter.lint_migrations()
-        self.assertTrue(has_errors)
+        linter = MigrationLinter(path)
+        linter.lint_all_migrations(git_commit_id=commit_id)
+        self.assertTrue(linter.has_errors)
 
     def _test_linter_finds_no_errors(self, path, commit_id=None):
-        linter = MigrationLinter(path, commit_id=commit_id)
-        has_errors = linter.lint_migrations()
-        self.assertFalse(has_errors)
+        linter = MigrationLinter(path)
+        linter.lint_all_migrations(git_commit_id=commit_id)
+        self.assertFalse(linter.has_errors)

tests/functional/test_multiple_calls.py

@@ -0,0 +1,23 @@
+import unittest
+
+from django_migration_linter import MigrationLinter
+from tests import fixtures
+
+class TestMultipleLinters(unittest.TestCase):
+    def test_multiple_linters(self):
+        l1 = MigrationLinter(fixtures.ADD_NOT_NULL_COLUMN_PROJECT)
+        l2 = MigrationLinter(fixtures.RENAME_COLUMN_PROJECT)
+        l3 = MigrationLinter(fixtures.CORRECT_PROJECT)
+
+        l1.lint_migration('test_app', '0002')
+        l2.lint_migration('test_app', '0002')
+        l3.lint_migration('test_app1', '0001')
+        l3.lint_migration('test_app1', '0002')
+
+        self.assertTrue(l1.has_errors)
+        self.assertTrue(l2.has_errors)
+        self.assertFalse(l3.has_errors)
+
+        self.assertEqual(l1.nb_total, 1)
+        self.assertEqual(l2.nb_total, 1)
+        self.assertEqual(l3.nb_total, 2)