Merge pull request #65 from parmentelat/debug-simple-trimino

added a failing test with 2 triminos on a 3x3 board

tests/test_trimino_based.py

@@ -0,0 +1,77 @@
+import pytest
+import numpy as np
+
+from exact_cover import get_exact_cover
+from exact_cover.error import NoSolution
+from exact_cover.io import DTYPE_FOR_ARRAY
+# from exact_cover.helpers import is_solution
+
+DTYPE = dict(dtype=DTYPE_FOR_ARRAY)
+
+# from exact_cover.io import load_problem
+
+# from tests.config import GLOBAL_CONFIG
+
+
+# one specific problem that I had trouble with
+# originally based on solving the trivial problem
+# of arranging 2 identical triminos on a 3x3 board
+
+#    +--+
+#    |  |
+# +--+--+
+# |  |  |
+# +--+--+
+
+# +--+--+--+
+# |xx|  |xx|
+# +--+--+--+
+# |  |  |  |
+# +--+--+--+
+# |xx|  |  |
+# +--+--+--+
+
+# the exact cover matrix built manually
+def input1():
+    to_cover = [
+        [1, 0, 0, 1, 1, 0, 1, 0],
+        [1, 0, 0, 0, 1, 1, 0, 1],
+        [1, 0, 0, 0, 1, 1, 1, 0],
+        [1, 0, 1, 0, 1, 1, 0, 0],
+        [1, 0, 0, 0, 1, 0, 1, 1],
+        [1, 0, 1, 1, 1, 0, 0, 0],  # <- 5
+        [1, 0, 0, 0, 0, 1, 1, 1],
+        [0, 1, 0, 1, 1, 0, 1, 0],
+        [0, 1, 0, 0, 1, 1, 0, 1],
+        [0, 1, 0, 0, 1, 1, 1, 0],
+        [0, 1, 1, 0, 1, 1, 0, 0],
+        [0, 1, 0, 0, 1, 0, 1, 1],
+        [0, 1, 1, 1, 1, 0, 0, 0],
+        [0, 1, 0, 0, 0, 1, 1, 1],  # <- 13
+    ]
+    return np.array(to_cover, **DTYPE)
+
+def input2():
+    return np.load("tests/files/small_trimino_problem.npy")
+
+def test_inputs_are_equal():
+    m1 = input1()
+    m2 = input2()
+
+    # really equal, including their dtype
+    assert (np.all(np.equal(m1, m2))
+            and (m1.dtype is m2.dtype)
+            and (m1.shape == m2.shape))
+
+def run_on_input(array, expected):
+    try:
+        solution = get_exact_cover(array)
+        assert np.all(solution == expected)
+    except NoSolution as exc:
+        pytest.fail(f"no solution found for {array}")
+
+def test_input1():
+    run_on_input(input1(), [5, 13])
+
+def test_input2():
+    run_on_input(input2(), [5, 13])