Add method for extracting .tar.gz to .tar

- Add decompress_tar_gz in TarKeywords to convert .tar.gz to .tar
  without extracting contents.
- Update deploy_images_to_local_registry in test_sanity.py to use
  decompress_tar_gz for node-hello-alpine.tar.gz.
- Ensure .tar.gz is properly decompressed before loading into the
  local registry.
- Previously, extract_tar_file was used, which fully extracted the tar
  contents instead of just converting to .tar.
- Fix minor linting issues in tar_keywords.

Change-Id: I88beb819c80360c7162921bb2e64c7080531be36
Signed-off-by: Andrew Vaillancourt <andrew.vaillancourt@windriver.com>

keywords/linux/tar/tar_keywords.py

@@ -10,14 +10,28 @@ class TarKeywords(BaseKeyword):
     def __init__(self, ssh_connection: SSHConnection):
         self.ssh_connection = ssh_connection
 
-    def extract_tar_file(self, file_name: str):
+    def extract_tar_file(self, file_name: str) -> None:
         """
-        Extracts the given tar file
+        Extracts the given tar file.
+
         Args:
-            file_name (): the name of the file
-
-        Returns:
-
+            file_name (str): the name of the file.
         """
-        self.ssh_connection.send(f'tar -xzvf {file_name}')
+        self.ssh_connection.send(f"tar -xzvf {file_name}")
+        self.validate_success_return_code(self.ssh_connection)
+
+    def decompress_tar_gz(self, file_name: str) -> None:
+        """
+        Decompresses a .tar.gz file into a .tar file without extracting contents.
+
+        Args:
+            file_name (str): The path to the .tar.gz file.
+
+        Raises:
+            ValueError: If the file does not have a .tar.gz extension.
+        """
+        if not file_name.endswith(".tar.gz"):
+            raise ValueError("File must be a .tar.gz archive.")
+
+        self.ssh_connection.send(f"gunzip -f {file_name}")
         self.validate_success_return_code(self.ssh_connection)

testcases/cloud_platform/sanity/test_sanity.py

@@ -1447,7 +1447,7 @@ def deploy_images_to_local_registry(ssh_connection: SSHConnection):
     docker_load_image_keywords.push_docker_image_to_registry("pv-test", local_registry)
 
     file_keywords.upload_file(get_stx_resource_path("resources/cloud_platform/images/node-hello-alpine/node-hello-alpine.tar.gz"), "/home/sysadmin/node-hello-alpine.tar.gz", overwrite=False)
-    TarKeywords(ssh_connection).extract_tar_file("/home/sysadmin/node-hello-alpine.tar.gz")
+    TarKeywords(ssh_connection).decompress_tar_gz("/home/sysadmin/node-hello-alpine.tar.gz")
     docker_load_image_keywords.load_docker_image_to_host("node-hello-alpine.tar")
     docker_load_image_keywords.tag_docker_image_for_registry("registry.local:9001/node-hello:alpine", "node-hello", local_registry)
     docker_load_image_keywords.push_docker_image_to_registry("node-hello", local_registry)