Implement version manager kata form codewars (5bc7bb444be9774f100000c3)

src/version_manager.py

@@ -0,0 +1,52 @@
+class VersionManager:
+    def __init__(self, version=""):
+        self.major_ = 0
+        self.minor_ = 0
+        self.patch_ = 0
+
+        if not version:
+            self.patch_ = 1
+        else:
+            parts = version.split(".")
+            try:
+                if len(parts) >= 1 and parts[0]:
+                    self.major_ = int(parts[0])
+                if len(parts) >= 2:
+                    self.minor_ = int(parts[1])
+                if len(parts) >= 3:
+                    self.patch_ = int(parts[2])
+            except ValueError:
+                raise ValueError("Error occured while parsing version!")
+
+        self.version_history = [(self.major_, self.minor_, self.patch_)]
+
+    def _save_history(self):
+        self.version_history.append((self.major_, self.minor_, self.patch_))
+
+    def major(self):
+        self._save_history()
+        self.major_ += 1
+        self.minor_ = 0
+        self.patch_ = 0
+        return self
+
+    def minor(self):
+        self._save_history()
+        self.minor_ += 1
+        self.patch_ = 0
+        return self
+
+    def patch(self):
+        self._save_history()
+        self.patch_ += 1
+        return self
+
+    def rollback(self):
+        if len(self.version_history) <= 1:
+            raise ValueError("Cannot rollback!")
+
+        self.major_, self.minor_, self.patch_ = self.version_history.pop()
+        return self
+
+    def release(self):
+        return f"{self.major_}.{self.minor_}.{self.patch_}"

tests/test_version_manager.py

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+from src.version_manager import VersionManager
+
+
+def run_tests():
+    # Test it_1: Initialization
+    assert VersionManager().release() == "0.0.1"
+    assert VersionManager("1.2.3").release() == "1.2.3"
+    assert VersionManager("1").release() == "1.0.0"
+
+    # Test it_5: Rollbacks
+    vm = VersionManager().major().rollback()
+    assert vm.release() == "0.0.1"
+
+    # Test it_7: Exception Handling
+    try:
+        VersionManager("a")
+    except Exception as e:
+        assert str(e) == "Error occured while parsing version!"
+
+    # Test it_8: Rollback failure
+    vm2 = VersionManager()
+    try:
+        vm2.rollback()
+    except Exception as e:
+        assert str(e) == "Cannot rollback!"
+
+    print("All tests passed!")
+
+
+run_tests()