NEW: Basic test setup

Start working on a test setup using fixtures for preparing a test image.
Currently, the test fails due to a weird circumstances. Accessing
`value.human_value` in the for loop in `test_MetadataHandler_fetch_key` causes a
segmentation fault.

misc/requirements/requirements_tests.txt

@@ -4,3 +4,4 @@ pytest-mock==3.5.1
 pytest-qt==3.3.0
 pytest-xvfb==2.0.0
 pytest-bdd==4.0.2
+Pillow==8.1.2

tests/conftest.py

@@ -190,3 +190,22 @@ def add_exif_information_impl(path: str, content):
         metadata.piexif.insert(metadata.piexif.dump(exif_dict), path)
 
     return add_exif_information_impl
+
+
+@pytest.fixture()
+def add_metadata_information():
+    """Fixture to retrieve a helper function that adds metadata content to an image."""
+
+    def add_metadata_information_impl(path: str, content):
+        assert (
+            metadata.pyexiv2 is not None
+        ), "pyexiv2 required to add metadata information"
+        _metadata = metadata.pyexiv2.ImageMetadata(path)
+        _metadata.read()
+
+        for key, value in content.items():
+            _metadata.__setitem__(key, value)
+
+        _metadata.write()
+
+    return add_metadata_information_impl

tests/unit/imutils/test_metadata.py

@@ -6,9 +6,24 @@
 
 """Tests for vimiv.imutils.metadata."""
 
+from fractions import Fraction
+from PyQt5.QtGui import QPixmap
+from PIL import Image
 import pytest
 
+from vimiv import imutils, utils
 from vimiv.imutils import metadata
+from vimiv.imutils.metadata import MetadataHandler
+
+try:
+    import piexif
+except ImportError:
+    piexif = None
+
+try:
+    import pyexiv2
+except ImportError:
+    pyexiv2 = None
 
 
 @pytest.fixture(
@@ -66,3 +81,58 @@ def test_handler_base_raises(methodname, args):
 def test_handler_exception_customization(handler, expected_msg):
     with pytest.raises(metadata.UnsupportedMetadataOperation, match=expected_msg):
         handler.raise_exception("test operation")
+
+
+@pytest.fixture()
+def metadata_content():
+    return {
+        "Exif.Image.Copyright": pyexiv2.exif.ExifTag(
+            "Exif.Image.Copyright", "vimiv-AUTHORS-2021"
+        ),
+        "Exif.Image.DateTime": pyexiv2.exif.ExifTag(
+            "Exif.Image.DateTime", "2017-12-16 16:21:57"
+        ),
+        "Exif.Image.Make": pyexiv2.exif.ExifTag("Exif.Image.Make", "vimiv"),
+        "Exif.Photo.ApertureValue": pyexiv2.exif.ExifTag(
+            "Exif.Photo.ApertureValue", Fraction(4)
+        ),
+        "Exif.Photo.ExposureTime": pyexiv2.exif.ExifTag(
+            "Exif.Photo.ExposureTime", Fraction(1, 25)
+        ),
+        "Exif.Photo.FocalLength": pyexiv2.exif.ExifTag(
+            "Exif.Photo.FocalLength", Fraction(600)
+        ),
+        "Exif.Photo.ISOSpeedRatings": pyexiv2.exif.ExifTag(
+            "Exif.Photo.ISOSpeedRatings", [320]
+        ),
+        "Exif.GPSInfo.GPSAltitude": pyexiv2.exif.ExifTag(
+            "Exif.GPSInfo.GPSAltitude", Fraction(2964)
+        )
+        # TODO: ADD IPTC
+    }
+
+
+@pytest.fixture()
+def dummy_image():
+    filename = "./image.jpg"
+    Image.new(mode="RGB", size=(300, 300), color="red").save(filename)
+    # QPixmap(*(300, 300)).save(filename)
+    return filename
+
+
+@pytest.fixture
+def get_MetadataHandler(add_metadata_information, dummy_image, metadata_content):
+    assert pyexiv2 is not None, "pyexiv2 required to add metadata information"
+    add_metadata_information(dummy_image, metadata_content)
+    return MetadataHandler(dummy_image)
+
+
+def test_MetadataHandler_fetch_key(get_MetadataHandler, metadata_content):
+    handler = get_MetadataHandler
+    for key, value in metadata_content.items():
+        data = handler.fetch_key(key)
+        assert data[0] == key
+        try:
+            assert data[2] == value.human_value
+        except AttributeError:
+            assert data[2] == value.raw_value