Parse checkmates but don't verify

chess/board.go

@@ -360,7 +360,7 @@ func (b *Board) Move(move string) error {
 	}
 
 	// make sure the move is marked as a check if it was
-	if b.InCheck() && !strings.HasSuffix(move, "+") {
+	if b.InCheck() && !strings.HasSuffix(move, "+") && !strings.HasSuffix(move, "#") {
 		move += "+"
 	}
 
@@ -379,6 +379,7 @@ func parseMove(move string) (string, int, int, string, error) {
 	)
 
 	move = strings.TrimSuffix(move, "+")
+	move = strings.TrimSuffix(move, "#")
 
 	if move == "O-O" {
 		return "K", 5, 7, "g1", nil

chess/board_test.go

@@ -472,6 +472,22 @@ func TestBoardCheck(t *testing.T) {
 	assertParse(t, b, "Kxf7")
 }
 
+func TestBoardCheckmate(t *testing.T) {
+	t.Parallel()
+
+	b := chess.NewBoard()
+
+	assert.False(t, b.InCheck())
+
+	// fool's mate
+	assertParse(t, b, "f3 e6 g4 Qh4#")
+
+	assert.True(t, b.InCheck())
+	assert.True(t, strings.HasSuffix(b.Moves[len(b.Moves)-1], "#"), "checkmate move should end with #")
+
+	assertMoveError(t, b, "a3", "invalid move a3: king is in check")
+}
+
 func TestBoardPin(t *testing.T) {
 	t.Parallel()