Merge pull request #66 from SamWhited/custom_rawkit_errors

Customize rawkit errors and don't use asserts

.gitignore

@@ -57,3 +57,5 @@ target/
 
 # Vim
 *.swp
+
+test-results/

Makefile

@@ -50,7 +50,7 @@ upload: build test
 clean:
 	$(ACTIVATE); $(MAKE) -C docs $@
 	find . -iname '*.pyc' | xargs rm -f
-	rm -rf docs/source/api/*
+	find . -iname '__pycache__' -type d | xargs rm -rf
 	rm -rf .tox
 	rm -rf dist
 	rm -rf $(VENV)

docs/source/api/rawkit.rst

@@ -9,6 +9,14 @@ rawkit package
 Submodules
 ----------
 
+rawkit.errors module
+----------------------
+
+.. automodule:: rawkit.errors
+    :members:
+    :undoc-members:
+    :show-inheritance:
+
 rawkit.metadata module
 ----------------------
 

rawkit/errors.py

@@ -0,0 +1,24 @@
+""":mod:`rawkit.errors` --- Errors thrown by rawkit
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+These errors are thrown by various rawkit functions and methods when things go
+wrong. They will only be raised by rawkit; for lower level errors raised by the
+underlying libraw bindings, see :class:`libraw.errors`.
+"""
+
+
+class InvalidFileType(ValueError):
+
+    """
+    Raised when an invalid file type or file extension is passed to a rawkit
+    method. If rawkit does not know what the filetype is, a
+    :exc:`libraw.errors.FileUnsupported` may be raised instead.
+    """
+
+
+class NoFileSpecified(ValueError):
+
+    """
+    Raised when the method or function excpects a `filename` argument, but no
+    file name (or a value of `None`) was specified.
+    """

rawkit/raw.py

@@ -7,6 +7,8 @@
 from libraw import libraw
 from libraw import errors as e
 
+
+from rawkit.errors import NoFileSpecified, InvalidFileType
 from rawkit.metadata import Metadata
 from rawkit.options import Options
 
@@ -31,10 +33,13 @@ class Raw(object):
     :type filename: :class:`str`
     :returns: A raw object
     :rtype: :class:`Raw`
+    :raises: :exc:`rawkit.errors.NoFileSpecified`
     """
 
     def __init__(self, filename=None):
         """Initializes a new Raw object."""
+        if filename is None:
+            raise NoFileSpecified()
         self.data = libraw.libraw_init(0)
         e.check_call(
             libraw.libraw_open_file(self.data, filename.encode('ascii'))
@@ -82,8 +87,13 @@ def save(self, filename=None, filetype='ppm'):
         :type filename: :class:`str`
         :param filetype: the type of file to output (``ppm`` or ``tiff``)
         :type filetype: :class:`str`
+        :raises: :exc:`rawkit.errors.NoFileSpecified`
+                 :exc:`rawkit.errors.InvalidFileTypeError`
         """
-        assert filetype in ('ppm', 'tiff')
+        if filename is None:
+            raise NoFileSpecified()
+        if filetype not in ('ppm', 'tiff'):
+            raise InvalidFileType('Output filetype must be "ppm" or "tiff"')
         self.data.contents.params.output_tiff = 0 if filetype is 'ppm' else 1
 
         self.unpack()

tests/unit/raw_test.py

@@ -1,5 +1,6 @@
 import mock
 import pytest
+from rawkit.errors import InvalidFileType, NoFileSpecified
 from rawkit.metadata import Metadata
 from rawkit.raw import Raw
 
@@ -41,6 +42,11 @@ def test_create(mock_libraw, raw, input_file):
     )
 
 
+def test_create_no_filename(mock_libraw):
+    with pytest.raises(NoFileSpecified):
+        Raw()
+
+
 def test_unpack(mock_libraw, raw):
     raw.unpack()
     mock_libraw.libraw_unpack.assert_called_once_with(raw.data)
@@ -72,6 +78,11 @@ def _test_save(mock_libraw, raw, output_file, filetype):
     )
 
 
+def test_save_no_filename(mock_libraw, raw):
+    with pytest.raises(NoFileSpecified):
+        raw.save(filetype='ppm')
+
+
 def test_save_ppm(mock_libraw, raw, output_file):
     _test_save(mock_libraw, raw, output_file, 'ppm')
 
@@ -81,7 +92,7 @@ def test_save_tiff(mock_libraw, raw, output_file):
 
 
 def test_save_invalid(mock_libraw, raw, output_file):
-    with pytest.raises(AssertionError):
+    with pytest.raises(InvalidFileType):
         _test_save(mock_libraw, raw, output_file, 'jpg')