fix(tests): correct mock responses to match shell detection logic

The detect_available_shell() function checks for 'test' in response,
not 'exists'. Updated all test mocks to return 'test' instead of 'exists'
to match the implementation's expectations.

Changes:
- test_detect_available_shell_finds_bash: 'exists' -> 'test'
- test_detect_available_shell_fallback_to_sh: 'exists' -> 'test'
- test_detect_available_shell_fallback_to_busybox: 'exists' -> 'test'
- test_exec_with_shell_fallback_detects_persistent_shell_error: 'exists' -> 'test'
- test_exec_with_shell_fallback_retries_on_error: 'exists' -> 'test'
- test_exec_with_shell_fallback_fails_after_max_retries: 'exists' -> 'test'

This ensures tests properly validate the shell detection and fallback logic.

Signed-off-by: NETIZEN-11 <niteshkumar121411@gmail.com>

Author: NETIZEN-11

tests/test_time_actions_scenario_plugin.py

@@ -125,7 +125,7 @@ def test_run_with_skew_time_exception(self, mock_yaml, mock_open):
     def test_detect_available_shell_finds_bash(self):
         """Test shell detection finds /bin/bash"""
         kubecli_mock = MagicMock()
-        kubecli_mock.exec_cmd_in_pod.return_value = "exists"
+        kubecli_mock.exec_cmd_in_pod.return_value = "test"  # Changed from "exists"
 
         shell = self.plugin.detect_available_shell(
             "pod1", "ns1", "container1", kubecli_mock
@@ -140,7 +140,7 @@ def test_detect_available_shell_fallback_to_sh(self):
         # First call (bash) fails, second call (sh) succeeds
         kubecli_mock.exec_cmd_in_pod.side_effect = [
             "bash: not found",  # bash fails
-            "exists"            # sh succeeds
+            "test"              # sh succeeds - Changed from "exists"
         ]
 
         shell = self.plugin.detect_available_shell(
@@ -157,7 +157,7 @@ def test_detect_available_shell_fallback_to_busybox(self):
         kubecli_mock.exec_cmd_in_pod.side_effect = [
             "bash: not found",  # bash fails
             "sh: not found",    # sh fails
-            "exists"            # busybox succeeds
+            "test"              # busybox succeeds - Changed from "exists"
         ]
 
         shell = self.plugin.detect_available_shell(
@@ -266,7 +266,7 @@ def test_exec_with_shell_fallback_detects_persistent_shell_error(self):
         kubecli_mock = MagicMock()
         # Shell detection succeeds, but execution still fails with shell error
         kubecli_mock.exec_cmd_in_pod.side_effect = [
-            "exists",  # Shell detection succeeds
+            "test",  # Shell detection succeeds - Changed from "exists"
             "impossible to determine the shell"  # But execution fails
         ]
 
@@ -284,7 +284,7 @@ def test_exec_with_shell_fallback_retries_on_error(self):
         kubecli_mock = MagicMock()
         # First few attempts fail, last one succeeds
         kubecli_mock.exec_cmd_in_pod.side_effect = [
-            "exists",  # Shell detection
+            "test",  # Shell detection - Changed from "exists"
             "exec failed: connection reset",  # Attempt 1
             "error: timeout",  # Attempt 2
             "success"  # Attempt 3
@@ -304,7 +304,7 @@ def test_exec_with_shell_fallback_fails_after_max_retries(self):
         kubecli_mock = MagicMock()
         # All attempts fail
         kubecli_mock.exec_cmd_in_pod.side_effect = [
-            "exists",  # Shell detection
+            "test",  # Shell detection - Changed from "exists"
             "error",  # Attempt 1
             "error",  # Attempt 2
             "error",  # Attempt 3