Add some test code

Will test the generation of grids for tiling
Run with `py.test`

Author: omad

.gitignore

@@ -57,4 +57,7 @@ docs/_build/
 target/
 
 # IntelliJ/PyCharm
-.idea
+.idea
+
+# Test stuff
+.hypothesis

setup.py

@@ -17,8 +17,13 @@
         'numpy',
         'netCDF4',
     ],
-    entry_points='''
-        [console_scripts]
-        datacube_ingest=ingestor.ingest_from_yaml:main
-    ''',
+    tests_require=[
+        'pytest',
+    ],
+
+    entry_points={
+      'console_scripts': [
+          'datacube_ingest = ingestor.ingest_from_yaml:main'
+      ]
+    },
 )

tests/__init__.py

@@ -0,0 +1,54 @@
+from collections import namedtuple
+
+# Implementation code
+
+TileDef = namedtuple('TileDef', 'xstart ystart xwidth ywidth')
+
+def create_grid_from_extent(width, height, xtile, ytile):
+
+    return [TileDef(xstart, ystart, xtile, ytile)
+            for xstart in xrange(0, width, xtile)
+            for ystart in xrange(0, height, ytile)]
+
+
+def round_up_divide(a, b):
+    """Divide a / b and round up. Integers"""
+    return (a+(-a%b))//b
+
+## Test Code
+ImageDef = namedtuple('ImageDef', 'width height tilewidth tileheight')
+def test_simple_grid():
+    imagedef = ImageDef(1000, 1000, 100, 100)
+    create_and_validate_grid(imagedef)
+
+def test_trivial_grid():
+    imagedef = ImageDef(100, 100, 100, 100)
+    create_and_validate_grid(imagedef)
+
+def test_slightly_larger_grid():
+    imagedef = ImageDef(1001, 1000, 100, 100)
+    create_and_validate_grid(imagedef)
+
+
+def create_and_validate_grid(imagedef):
+    tiles = create_grid_from_extent(*imagedef)
+
+    num_expected_tiles = round_up_divide(imagedef.width, imagedef.tilewidth) * round_up_divide(imagedef.height, imagedef.tileheight)
+    assert(len(tiles) == num_expected_tiles)
+    total_width = 0
+    for t in tiles:
+        if t.ystart == 0:
+            total_width += t.xwidth
+        assert(type(t) == TileDef)
+        assert(t.xwidth <= imagedef.tilewidth)
+        assert(t.xstart < imagedef.width)
+        assert(t.xstart + t.xwidth <= imagedef.width + imagedef.tilewidth)
+
+    assert(total_width >= imagedef.width)
+
+
+def test_expanded_extents():
+    pass
+
+def test_gridded_geo_box():
+    pass