add find_latest_version

src/dac/_version_management.py

@@ -0,0 +1,23 @@
+import re
+import subprocess
+from typing import Optional
+
+
+def find_latest_version(library_name: str, major: Optional[int] = None) -> str:
+    output = subprocess.check_output(
+        [
+            "pip",
+            "install",
+            "--no-deps",
+            "--ignore-installed",
+            "--no-cache-dir",
+            "--dry-run",
+            f"{library_name}{f'=={major}.*' if major is not None else ''}",
+        ],
+        stderr=subprocess.DEVNULL,
+    )
+    last_line = output.decode("utf-8").splitlines()[-1]
+    regex_rule = f"{library_name.replace('_', '-')}-{major if major is not None else ''}.[^ ]+"
+    match = re.search(regex_rule, last_line)
+    assert match is not None
+    return match[0][len(f"{library_name}-") :]

test/integration_test/version_management_test.py

@@ -0,0 +1,15 @@
+import pytest
+from dac._version_management import find_latest_version
+
+
+def test_if_find_latest_version_is_called_then_return_latest_version():
+    assert "0.5" == find_latest_version(library_name="rainbow-server")
+
+
+def test_if_find_latest_version_is_called_with_major_constraint_then_return_latest_major_version():
+    assert "0.25.3" == find_latest_version(library_name="pandas", major=0)
+
+
+def test_if_pkg_does_not_exist_then_find_package_return_none():
+    with pytest.raises(Exception):
+        find_latest_version(library_name="non-existing-package")