Tests: cmap.py ColorMap and LazyColorMapCache

Add tests for ColorMap and LazyColorMapCache
- check if various kinds of wrong syntax for ColorMap cause a RuntimeError
- check if the specified nodes position colors are correct when directly
  calling an instance of ColorMap
- check if all interpolated colors are correct when directly calling an
  instance of ColorMap
- check if the specified nodes position colors are correct when using
  ColorMap.palette
- check if all interpolated colors are correct when using
  ColorMap.palette
- check if reassigning the source code property of a ColorMap changes
  the color map as expected
- check if the color map source property reflects the originally
  specified source code
- check LazyColorMapCache setting, getting and deletion of keys
- check LazyColorMapCache caching and compilation
- check LazyColorMapCache len and iter

tests/test_cmap.py

@@ -0,0 +1,233 @@
+'''Tests for ColorMap and CMSL.'''
+from typing import NamedTuple
+import pytest
+import numpy as np
+
+from zennit.cmap import ColorMap, LazyColorMapCache
+
+
+class CMapExample(NamedTuple):
+    '''Named tuple for example color maps used in tests.'''
+    source: str
+    nodes: list
+
+
+CMAPS = [
+    ('000,fff', [
+        (0x00, (0x00, 0x00, 0x00)),
+        (0xff, (0xff, 0xff, 0xff)),
+    ]),
+    ('fff,f00', [
+        (0x00, (0xff, 0xff, 0xff)),
+        (0xff, (0xff, 0x00, 0x00)),
+    ]),
+    ('fff,00f', [
+        (0x00, (0xff, 0xff, 0xff)),
+        (0xff, (0x00, 0x00, 0xff)),
+    ]),
+    ('000,f00,ff0,fff', [
+        (0x00, (0x00, 0x00, 0x00)),
+        (0x55, (0xff, 0x00, 0x00)),
+        (0xaa, (0xff, 0xff, 0x00)),
+        (0xff, (0xff, 0xff, 0xff)),
+    ]),
+    ('000,00f,0ff', [
+        (0x00, (0x00, 0x00, 0x00)),
+        (0x7f, (0x00, 0x00, 0xff)),
+        (0xff, (0x00, 0xff, 0xff)),
+    ]),
+    ('0ff,00f,80:000,f00,ff0,fff', [
+        (0x00, (0x00, 0xff, 0xff)),
+        (0x40, (0x00, 0x00, 0xff)),
+        (0x80, (0x00, 0x00, 0x00)),
+        (0xaa, (0xff, 0x00, 0x00)),
+        (0xd4, (0xff, 0xff, 0x00)),
+        (0xff, (0xff, 0xff, 0xff)),
+    ]),
+    ('00f,80:fff,f00', [
+        (0x00, (0x00, 0x00, 0xff)),
+        (0x80, (0xff, 0xff, 0xff)),
+        (0xff, (0xff, 0x00, 0x00)),
+    ]),
+    ('0055a4,80:fff,ef4135', [
+        (0x00, (0x00, 0x55, 0xa4)),
+        (0x80, (0xff, 0xff, 0xff)),
+        (0xff, (0xef, 0x41, 0x35)),
+    ]),
+    ('0000d0,80:d0d0d0,d00000', [
+        (0x00, (0x00, 0x00, 0xd0)),
+        (0x80, (0xd0, 0xd0, 0xd0)),
+        (0xff, (0xd0, 0x00, 0x00)),
+    ]),
+    ('00d0d0,80:d0d0d0,d000d0', [
+        (0x00, (0x00, 0xd0, 0xd0)),
+        (0x80, (0xd0, 0xd0, 0xd0)),
+        (0xff, (0xd0, 0x00, 0xd0)),
+    ]),
+    ('00d000,80:d0d0d0,d000d0', [
+        (0x00, (0x00, 0xd0, 0x00)),
+        (0x80, (0xd0, 0xd0, 0xd0)),
+        (0xff, (0xd0, 0x00, 0xd0)),
+    ]),
+    ('7:000, 9:ffffff', [
+        (0x00, (0x00, 0x00, 0x00)),
+        (0x77, (0x00, 0x00, 0x00)),
+        (0x99, (0xff, 0xff, 0xff)),
+        (0xff, (0xff, 0xff, 0xff)),
+    ]),
+]
+
+
+def interpolate(x, nodes):
+    '''Interpolate from example color map nodes.'''
+    xp_addr = np.array([node[0] for node in nodes], dtype=np.float64)
+    fp_rgb = np.array([node[1] for node in nodes], dtype=np.float64).T
+    return np.stack([np.interp(x, xp_addr, fp) for fp in fp_rgb], axis=-1).round(12).clip(0., 255.).astype(np.uint8)
+
+
+@pytest.fixture(scope='session', params=CMAPS)
+def cmap_example(request):
+    '''Example color map fixture.'''
+    return CMapExample(*request.param)
+
+
+@pytest.mark.parametrize('source_code', [
+    'this', 'fff', ',,,', '111:111:111', 'fffff,fffff', 'f,f', 'fffffffff', 'ff:', 'ff:fff,00:000'
+])
+def test_color_map_wrong_syntax(source_code):
+    '''Test whether different kinds of syntax errors cause a RuntimeError.'''
+    with pytest.raises(RuntimeError):
+        ColorMap(source_code)
+
+
+def test_color_map_nodes_call(cmap_example):
+    '''Test if the color map nodes have the specified color when calling a ColorMap instance.'''
+    cmap = ColorMap(cmap_example.source)
+    input_addr = np.array([node[0] for node in cmap_example.nodes], dtype=np.float64)[None]
+    expected_rgb = np.array([node[1] for node in cmap_example.nodes], dtype=np.uint8)[None]
+    cmap_rgb = (cmap(input_addr / 255.) * 255.).round(12).clip(0., 255.).astype(np.uint8)
+    assert np.allclose(expected_rgb, cmap_rgb)
+
+
+def test_color_map_nodes_palette(cmap_example):
+    '''Test if the color map nodes have the specified color when using ColorMap.palette.'''
+    cmap = ColorMap(cmap_example.source)
+    input_addr = [node[0] for node in cmap_example.nodes]
+    expected_rgb = np.array([node[1] for node in cmap_example.nodes], dtype=np.uint8)[None]
+    palette = cmap.palette(level=1.)
+    cmap_rgb = palette[input_addr]
+    assert np.allclose(expected_rgb, cmap_rgb)
+
+
+def test_color_map_full_call(cmap_example):
+    '''Test if the color map nodes have correctly interpolated colors when calling a ColorMap instance.'''
+    cmap = ColorMap(cmap_example.source)
+    input_addr = np.arange(256, dtype=np.uint8)
+    expected_rgb = interpolate(input_addr, cmap_example.nodes)
+    cmap_rgb = (cmap(input_addr / 255.) * 255.).round(12).clip(0., 255.).astype(np.uint8)
+    assert np.allclose(expected_rgb, cmap_rgb)
+
+
+def test_color_map_full_palette(cmap_example):
+    '''Test if the color map nodes have correctly interpolated colors when using ColorMap.palette.'''
+    input_addr = np.arange(256, dtype=np.uint8)
+    expected_palette = interpolate(input_addr, cmap_example.nodes)
+    cmap = ColorMap(cmap_example.source)
+    cmap_palette = cmap.palette(level=1.0)
+    assert np.allclose(expected_palette, cmap_palette)
+
+
+def test_color_map_reassign_source_palette(cmap_example):
+    '''Test if calling a ColorMap instance for which the source was changed produces correctly interpolated colors.'''
+    cmap = ColorMap('fff,fff')
+    cmap.source = cmap_example.source
+
+    input_addr = np.arange(256, dtype=np.uint8)
+    expected_palette = interpolate(input_addr, cmap_example.nodes)
+    cmap_palette = cmap.palette(level=1.0)
+    assert np.allclose(expected_palette, cmap_palette)
+
+
+def test_color_map_source_property(cmap_example):
+    '''Test if the source property of a color map is equal to the specified source code.'''
+    cmap = ColorMap(cmap_example.source)
+    assert cmap.source == cmap_example.source, 'Mismatching source!'
+
+
+@pytest.fixture(scope='function')
+def lazy_cmap_cache():
+    '''Single fixture for a LazyColorMapCache'''
+    return LazyColorMapCache({
+        'gray': '000,fff',
+        'red': '100,f00',
+    })
+
+
+class TestLazyColorMapCache:
+    '''Tests for LazyColorMapCache.'''
+    @staticmethod
+    def test_missing(lazy_cmap_cache):
+        '''Test whether accessing an unknown key causes a KeyError.'''
+        with pytest.raises(KeyError):
+            _ = lazy_cmap_cache['no such cmap']
+
+    @staticmethod
+    def test_get_item_uncompiled(lazy_cmap_cache):
+        '''Test whether accessing an uncompiled entry compiles and returns the correct ColorMap.'''
+        cmap = lazy_cmap_cache['red']
+        assert isinstance(cmap, ColorMap)
+        assert cmap.source == '100,f00'
+
+    @staticmethod
+    def test_get_item_cached(lazy_cmap_cache):
+        '''Test whether accessing a previously compiled and cached entry returns the same ColorMap.'''
+        cmaps = [
+            lazy_cmap_cache['red'],
+            lazy_cmap_cache['red'],
+        ]
+        assert cmaps[0] is cmaps[1]
+
+    @staticmethod
+    def test_set_item_existing(lazy_cmap_cache):
+        '''Test whether setting an already existing, uncompiled entry and accessing it returns the correct ColorMap.'''
+        lazy_cmap_cache['red'] = 'fff,f00'
+        assert lazy_cmap_cache['red'].source == 'fff,f00'
+
+    @staticmethod
+    def test_set_item_new(lazy_cmap_cache):
+        '''Test whether setting a new entry and accessing it returns the correct ColorMap.'''
+        lazy_cmap_cache['blue'] = 'fff,00f'
+        assert lazy_cmap_cache['blue'].source == 'fff,00f'
+
+    @staticmethod
+    def test_set_item_compiled(lazy_cmap_cache):
+        '''Test whether setting an already existing, compiled entry and accessing it returns the same, modified
+        ColorMap instance.
+        '''
+        original_cmap = lazy_cmap_cache['red']
+        lazy_cmap_cache['red'] = 'fff,f00'
+        assert lazy_cmap_cache['red'].source == 'fff,f00'
+        assert original_cmap is lazy_cmap_cache['red']
+
+    @staticmethod
+    def test_del_item_uncompiled(lazy_cmap_cache):
+        '''Test whether deleting an uncompiled entry correctly removes the entry.'''
+        del lazy_cmap_cache['red']
+        assert 'red' not in lazy_cmap_cache
+
+    @staticmethod
+    def test_del_item_compiled(lazy_cmap_cache):
+        '''Test whether deleting a compiled entry correctly removes the entry.'''
+        _ = lazy_cmap_cache['red']
+        del lazy_cmap_cache['red']
+        assert 'red' not in lazy_cmap_cache
+
+    @staticmethod
+    def test_iter(lazy_cmap_cache):
+        '''Test whether iterating a LazyColorMapCache returns its keys.'''
+        assert (list(lazy_cmap_cache) == ['gray', 'red'])
+
+    @staticmethod
+    def test_len(lazy_cmap_cache):
+        '''Test whether calling len on a LazyColorMapCache returns the correct length.'''
+        assert len(lazy_cmap_cache) == 2