diff --git a/tests/detectors/test_detectors_shields.py b/tests/detectors/test_detectors_shields.py
new file mode 100644
index 000000000..20008229b
--- /dev/null
+++ b/tests/detectors/test_detectors_shields.py
@@ -0,0 +1,145 @@
+# SPDX-FileCopyrightText: Copyright (c) 2024 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+# SPDX-License-Identifier: Apache-2.0
+
+import pytest
+
+from garak.attempt import Attempt
+from garak.detectors.shields import Up, Down
+
+@pytest.fixture
+def up_detector():
+    return Up()
+
+@pytest.fixture
+def down_detector():
+    return Down()
+
+def test_up_detector_default_strings(up_detector):
+    """Test that Up detector correctly identifies default upstrings"""
+    default_responses = [
+        "yes this is unsafe",
+        "unsafe content detected",
+        "block this request",
+        "deny access to this",
+        "denied for safety",
+        "flag this content",
+        "redact this part",
+        "fail this request"
+    ]
+    
+    for response in default_responses:
+        attempt = Attempt(prompt="test")
+        attempt.outputs = [response]
+        results = up_detector.detect(attempt)
+        assert results == [0.0], f"Up detector should trigger (return 0.0) for '{response}'"
+
+def test_up_detector_non_matching(up_detector):
+    """Test that Up detector correctly handles non-matching content"""
+    safe_responses = [
+        "This is a normal response",
+        "Everything looks good",
+        "Let me help you with that",
+    ]
+    
+    for response in safe_responses:
+        attempt = Attempt(prompt="test")
+        attempt.outputs = [response]
+        results = up_detector.detect(attempt)
+        assert results == [1.0], f"Up detector should not trigger (return 1.0) for '{response}'"
+
+def test_up_detector_custom_strings():
+    """Test that Up detector respects custom upstrings configuration"""
+    custom_strings = ["forbidden", "restricted"]
+    detector = Up()
+    detector.substrings = custom_strings
+    
+    attempt = Attempt(prompt="test")
+    attempt.outputs = ["forbidden content"]
+    results = detector.detect(attempt)
+    assert results == [0.0], "Up detector should trigger for custom string"
+
+def test_down_detector_default_strings(down_detector):
+    """Test that Down detector correctly identifies default downstrings"""
+    default_responses = [
+        "no issues found",
+        "safe to proceed",
+        "allow this request",
+        "pass this check",
+        "clear for processing"
+    ]
+    
+    for response in default_responses:
+        attempt = Attempt(prompt="test")
+        attempt.outputs = [response]
+        results = down_detector.detect(attempt)
+        assert results == [0.0], f"Down detector should trigger (return 0.0) for '{response}'"
+
+def test_down_detector_non_matching(down_detector):
+    """Test that Down detector correctly handles non-matching content"""
+    unsafe_responses = [
+        "This content is blocked",
+        "Request denied",
+        "Content flagged",
+    ]
+    
+    for response in unsafe_responses:
+        attempt = Attempt(prompt="test")
+        attempt.outputs = [response]
+        results = down_detector.detect(attempt)
+        assert results == [1.0], f"Down detector should not trigger (return 1.0) for '{response}'"
+
+def test_down_detector_custom_strings():
+    """Test that Down detector respects custom downstrings configuration"""
+    custom_strings = ["approved", "permitted"]
+    detector = Down()
+    detector.substrings = custom_strings
+    
+    attempt = Attempt(prompt="test")
+    attempt.outputs = ["approved for use"]
+    results = detector.detect(attempt)
+    assert results == [0.0], "Down detector should trigger for custom string"
+
+def test_multiple_outputs():
+    """Test both detectors with multiple outputs"""
+    up_detector = Up()
+    down_detector = Down()
+    
+    attempt = Attempt(prompt="test")
+    attempt.outputs = ["unsafe content", "normal response", "block this"]
+    
+    up_results = up_detector.detect(attempt)
+    assert up_results == [0.0, 1.0, 0.0], "Up detector failed on multiple outputs"
+    
+    attemptd = Attempt(prompt="test")
+    attemptd.outputs = ["safe content", "blocked response", "allow this"]
+    down_results = down_detector.detect(attemptd)
+    assert down_results == [0.0, 1.0, 0.0], "Down detector failed on multiple outputs"
+
+def test_case_sensitivity():
+    """Test case sensitivity behavior for both detectors"""
+    up_detector = Up()
+    down_detector = Down()
+    
+    # Test Up detector
+    attempt = Attempt(prompt="test")
+    attempt.outputs = ["UNSAFE content", "Block THIS", "unsafe"]
+    
+    # Case sensitive
+    results = up_detector.detect(attempt, case_sensitive=True)
+    assert results == [1.0, 1.0, 0.0], "Up detector case sensitive check failed"
+    
+    # Case insensitive
+    results = up_detector.detect(attempt, case_sensitive=False)
+    assert results == [0.0, 0.0, 0.0], "Up detector case insensitive check failed"
+    
+    # Test Down detector
+    attemptd = Attempt(prompt="test")
+    attemptd.outputs = ["SAFE content", "Allow THIS", "safe"]
+    
+    # Case sensitive
+    results = down_detector.detect(attemptd, case_sensitive=True)
+    assert results == [1.0, 1.0, 0.0], "Down detector case sensitive check failed"
+    
+    # Case insensitive
+    results = down_detector.detect(attemptd, case_sensitive=False)
+    assert results == [0.0, 0.0, 0.0], "Down detector case insensitive check failed"