python-constraint · harmehak0173 · Aug 14, 2026 · Aug 14, 2026
diff --git a/examples/crosswords/crosswords.py b/examples/crosswords/crosswords.py
@@ -6,7 +6,7 @@
 MINLEN = 3
 
 
-def main(puzzle, lines):
+def solve(puzzle, lines):
     puzzle = puzzle.rstrip().splitlines()
     while puzzle and not puzzle[0]:
         del puzzle[0]
@@ -60,10 +60,6 @@ def main(puzzle, lines):
             del word[:]
         col += 1
 
-    # hnames = ["h%d" % i for i in range(len(horizontal))]
-    # vnames = ["v%d" % i for i in range(len(vertical))]
-
-    # problem = Problem(MinConflictsSolver())
     problem = Problem()
 
     for hi, hword in enumerate(horizontal):
@@ -116,7 +112,7 @@ def main(puzzle, lines):
 
     solution = problem.getSolution()
     if not solution:
-        print("No solution found!")
+        return None, []
 
     maxcol = 0
     maxrow = 0
@@ -145,8 +141,16 @@ def main(puzzle, lines):
         for (row, col), char in zip(word, solution[variable]):
             matrix[row][col] = char
 
-    for row in range(maxrow + 1):
-        for col in range(maxcol + 1):
+    return solution, matrix
+
+
+def main(puzzle, lines):
+    solution, matrix = solve(puzzle, lines)
+    if not solution:
+        print("No solution found!")
+        return
+    for row in range(len(matrix)):
+        for col in range(len(matrix[row])):
             sys.stdout.write(matrix[row][col])
         sys.stdout.write("\n")
 

diff --git a/pyproject.toml b/pyproject.toml
@@ -107,7 +107,7 @@ select = [
 convention = "google"
 
 [tool.pytest.ini_options]
-minversion = "9.1.1"
+minversion = "8.0.0"
 pythonpath = [
     "constraint",
 ] # necessary to get coverage reports without installing with `-e`

diff --git a/tests/test_examples.py b/tests/test_examples.py
@@ -0,0 +1,64 @@
+"""Tests for python-constraint example solvers."""
+
+from examples.crosswords import crosswords
+from examples.sudoku import sudoku
+from examples.wordmath import seisseisdoze, sendmoremoney, twotwofour
+from examples.xsum import xsum
+
+
+def test_sudoku():
+    """Verify that sudoku solver returns valid 9x9 solutions."""
+    solutions = sudoku.solve()
+    assert len(solutions) >= 1
+    sol = solutions[0]
+    assert sol[12] == 9
+    row1 = [sol[10 + col] for col in range(1, 10)]
+    assert sorted(row1) == list(range(1, 10))
+
+
+def test_sendmoremoney():
+    """Verify cryptarithmetic solution for SEND+MORE=MONEY."""
+    solutions = sendmoremoney.solve()
+    assert len(solutions) == 1
+    s = solutions[0]
+    assert s["s"] == 9 and s["e"] == 5 and s["m"] == 1 and s["y"] == 2
+
+
+def test_twotwofour():
+    """Verify cryptarithmetic solution for TWO+TWO=FOUR."""
+    solutions = twotwofour.solve()
+    assert len(solutions) > 0
+    for s in solutions:
+        two = s["t"] * 100 + s["w"] * 10 + s["o"]
+        four = s["f"] * 1000 + s["o"] * 100 + s["u"] * 10 + s["r"]
+        assert 2 * two == four
+
+
+def test_seisseisdoze():
+    """Verify cryptarithmetic solution for SEIS+SEIS=DOZE."""
+    solutions = seisseisdoze.solve()
+    assert len(solutions) > 0
+    for s in solutions:
+        seis = s["s"] * 1000 + s["e"] * 100 + s["i"] * 10 + s["s"]
+        doze = s["d"] * 1000 + s["o"] * 100 + s["z"] * 10 + s["e"]
+        assert 2 * seis == doze
+
+
+def test_xsum():
+    """Verify xsum solver where each 5-number row sums to 27."""
+    solutions = xsum.solve()
+    assert len(solutions) > 0
+    for s in solutions:
+        row1_sum = s["a"] + s["b"] + s["c"] + s["d"] + s["x"]
+        row2_sum = s["e"] + s["f"] + s["g"] + s["h"] + s["x"]
+        assert row1_sum == 27
+        assert row2_sum == 27
+
+
+def test_crosswords():
+    """Verify crossword puzzle solver execution with sample mask and word list."""
+    puzzle = "####\n####\n####\n####"
+    words = ["DATA", "CODE", "TEST", "MATH", "BYTE", "DISK", "FILE", "FLOW"]
+    solution, matrix = crosswords.solve(puzzle, words)
+    assert isinstance(matrix, list)
+