test: expand test coverage with comprehensive exception and client tests

- Added tests for all exception types including APIError context
- Added comprehensive client tests including env var handling
- Added tests for context manager and direct API methods
- All tests pass locally, ready for CI validation

Author: jdrhyne

tests/unit/test_client.py

@@ -1,9 +1,72 @@
 """Unit tests for NutrientClient."""
 
+import os
+from unittest.mock import patch
+
 from nutrient_dws.client import NutrientClient
 
 
-def test_client_init():
-    """Test client initialization."""
+def test_client_init_with_api_key():
+    """Test client initialization with API key."""
     client = NutrientClient(api_key="test-key")
     assert client is not None
+    assert client._http_client._api_key == "test-key"
+
+
+def test_client_init_with_env_var():
+    """Test client initialization with environment variable."""
+    with patch.dict(os.environ, {"NUTRIENT_API_KEY": "env-key"}):
+        client = NutrientClient()
+        assert client._http_client._api_key == "env-key"
+
+
+def test_client_init_precedence():
+    """Test that explicit API key takes precedence over env var."""
+    with patch.dict(os.environ, {"NUTRIENT_API_KEY": "env-key"}):
+        client = NutrientClient(api_key="explicit-key")
+        assert client._http_client._api_key == "explicit-key"
+
+
+def test_client_build_method():
+    """Test that build() returns a BuildAPIWrapper."""
+    client = NutrientClient(api_key="test-key")
+    builder = client.build("test.pdf")
+
+    # Check class name to avoid import issues
+    assert builder.__class__.__name__ == "BuildAPIWrapper"
+
+
+def test_client_has_direct_api_methods():
+    """Test that client has direct API methods."""
+    client = NutrientClient(api_key="test-key")
+
+    # Check that direct API methods exist (from DirectAPIMixin)
+    assert hasattr(client, "convert_to_pdf")
+    assert hasattr(client, "flatten_annotations")
+    assert hasattr(client, "rotate_pages")
+    assert hasattr(client, "watermark_pdf")
+    assert hasattr(client, "ocr_pdf")
+    assert hasattr(client, "apply_redactions")
+    assert hasattr(client, "merge_pdfs")
+
+
+def test_client_context_manager():
+    """Test client can be used as context manager."""
+    with NutrientClient(api_key="test-key") as client:
+        assert client is not None
+        # Check that HTTP client is not closed
+        assert hasattr(client._http_client, "_session")
+
+    # After exiting context, HTTP client session should be closed
+    # We can't directly check if closed, but the method should have been called
+
+
+def test_client_close():
+    """Test client close method."""
+    client = NutrientClient(api_key="test-key")
+
+    # Verify HTTP client exists
+    assert hasattr(client, "_http_client")
+
+    # Close should not raise an error
+    client.close()

tests/unit/test_exceptions.py

@@ -3,7 +3,10 @@
 from nutrient_dws.exceptions import (
     APIError,
     AuthenticationError,
+    FileProcessingError,
     NutrientError,
+    NutrientTimeoutError,
+    ValidationError,
 )
 
 
@@ -21,8 +24,63 @@ def test_authentication_error():
     assert isinstance(exc, NutrientError)
 
 
-def test_api_error():
-    """Test API error."""
+def test_api_error_basic():
+    """Test API error without additional context."""
     exc = APIError("API request failed")
     assert str(exc) == "API request failed"
     assert isinstance(exc, NutrientError)
+    assert exc.status_code is None
+    assert exc.response_body is None
+    assert exc.request_id is None
+
+
+def test_api_error_with_status():
+    """Test API error with status code."""
+    exc = APIError("Not found", status_code=404)
+    assert exc.status_code == 404
+    assert "Status: 404" in str(exc)
+
+
+def test_api_error_full_context():
+    """Test API error with all context."""
+    exc = APIError(
+        "Server error",
+        status_code=500,
+        response_body='{"error": "Internal server error"}',
+        request_id="req-123",
+    )
+    assert exc.status_code == 500
+    assert exc.response_body == '{"error": "Internal server error"}'
+    assert exc.request_id == "req-123"
+    assert "Status: 500" in str(exc)
+    assert "Request ID: req-123" in str(exc)
+    assert "Response:" in str(exc)
+
+
+def test_validation_error():
+    """Test validation error."""
+    exc = ValidationError("Invalid input")
+    assert str(exc) == "Invalid input"
+    assert isinstance(exc, NutrientError)
+    assert exc.errors == {}
+
+
+def test_validation_error_with_details():
+    """Test validation error with error details."""
+    errors = {"field": "Invalid value"}
+    exc = ValidationError("Validation failed", errors=errors)
+    assert exc.errors == errors
+
+
+def test_timeout_error():
+    """Test timeout error."""
+    exc = NutrientTimeoutError("Request timed out")
+    assert str(exc) == "Request timed out"
+    assert isinstance(exc, NutrientError)
+
+
+def test_file_processing_error():
+    """Test file processing error."""
+    exc = FileProcessingError("Failed to process file")
+    assert str(exc) == "Failed to process file"
+    assert isinstance(exc, NutrientError)