Add basic image-mode tests and strengthen argument handling in from_a…

…rray_info()

toasty/image.py

@@ -149,6 +149,9 @@ class ImageMode(Enum):
 
     @classmethod
     def from_array_info(cls, shape, dtype):
+        # Make sure we have an actual dtype instance to work with:
+        dtype = np.dtype(dtype)
+
         if len(shape) == 2:
             if dtype.kind == "f" and dtype.itemsize == 4:
                 return cls.F32

toasty/tests/test_modes.py

@@ -0,0 +1,62 @@
+# -*- mode: python; coding: utf-8 -*-
+# Copyright 2022 the AAS WorldWide Telescope project
+# Licensed under the MIT License.
+
+import numpy as np
+import pytest
+
+from ..image import Image, ImageMode
+
+
+class ModeInfo(object):
+    def __init__(self, mode, dtype, demo_shape, default_format):
+        self.mode = mode
+        self.dtype = dtype
+        self.demo_shape = demo_shape
+        self.default_format = default_format
+
+
+MODE_INFO = [
+    ModeInfo(ImageMode.RGB, np.uint8, (10, 10, 3), "png"),
+    ModeInfo(ImageMode.RGBA, np.uint8, (10, 10, 4), "png"),
+    ModeInfo(ImageMode.F32, np.float32, (10, 10), "npy"),
+    ModeInfo(ImageMode.F64, np.float64, (10, 10), "npy"),
+    ModeInfo(ImageMode.F16x3, np.float16, (10, 10, 3), "npy"),
+    ModeInfo(ImageMode.U8, np.uint8, (10, 10), "npy"),
+    ModeInfo(ImageMode.I32, np.int32, (10, 10), "npy"),
+]
+
+
+def test_from_array_info():
+    for mi in MODE_INFO:
+        assert ImageMode.from_array_info(mi.demo_shape, mi.dtype) == mi.mode
+
+    with pytest.raises(ValueError):
+        s = (10, 10)
+        ImageMode.from_array_info(s, np.complex64)
+
+        s = (10, 10, 3)
+        ImageMode.from_array_info(s, np.float32)
+
+        s = (10, 10, 4)
+        ImageMode.from_array_info(s, np.int8)
+
+
+def test_image_interface():
+    for mi in MODE_INFO:
+        arr = np.zeros(mi.demo_shape, dtype=mi.dtype)
+        img = Image.from_array(arr)
+        img._default_format = None
+        assert img.default_format == mi.default_format
+        mb = mi.mode.make_maskable_buffer(8, 8)
+        img.fill_into_maskable_buffer(
+            mb, slice(1, 5), slice(1, 5), slice(4, 8), slice(4, 8)
+        )
+
+        mb.asarray().fill(1)
+        img.update_into_maskable_buffer(
+            mb, slice(1, 5), slice(1, 5), slice(4, 8), slice(4, 8)
+        )
+        assert mb.asarray().flat[0] == 1
+
+        img.clear()