test: Add minimal test for Matrix

Add a few tests for the Matrix class. This is not full fledged but at
least a starter.

Signed-off-by: Stefan Klug <stefan.klug@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>

test/matrix.cpp

@@ -0,0 +1,53 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2024, Ideas on Board Oy
+ *
+ * Matrix tests
+ */
+
+#include "libcamera/internal/matrix.h"
+
+#include <cmath>
+#include <iostream>
+
+#include "test.h"
+
+using namespace libcamera;
+
+#define ASSERT_EQ(a, b)                                                   \
+	if ((a) != (b)) {                                                 \
+		std::cout << #a " != " #b << " (line " << __LINE__ << ")" \
+			  << std::endl;                                   \
+		return TestFail;                                          \
+	}
+
+class MatrixTest : public Test
+{
+protected:
+	int run()
+	{
+		Matrix<double, 3, 3> m1;
+
+		ASSERT_EQ(m1[0][0], 0.0);
+		ASSERT_EQ(m1[0][1], 0.0);
+
+		constexpr Matrix<float, 2, 2> m2 = Matrix<float, 2, 2>().identity();
+		ASSERT_EQ(m2[0][0], 1.0);
+		ASSERT_EQ(m2[0][1], 0.0);
+		ASSERT_EQ(m2[1][0], 0.0);
+		ASSERT_EQ(m2[1][1], 1.0);
+
+		Matrix<float, 2, 2> m3{ { 2.0, 0.0, 0.0, 2.0 } };
+		Matrix<float, 2, 2> m4 = m3.inverse();
+
+		Matrix<float, 2, 2> m5 = m3 * m4;
+		ASSERT_EQ(m5[0][0], 1.0);
+		ASSERT_EQ(m5[0][1], 0.0);
+		ASSERT_EQ(m5[1][0], 0.0);
+		ASSERT_EQ(m5[1][1], 1.0);
+
+		return TestPass;
+	}
+};
+
+TEST_REGISTER(MatrixTest)