Set AssertError to inherit from std::runtime_error

The main interest is that one can now check more precisely the type of raised errors in unit tests

tests/test_TinyMatrix.cpp

@@ -24,6 +24,7 @@ TEST_CASE("TinyMatrix", "[algebra]")
            (A(1, 2) == 6) and (A(2, 0) == 7) and (A(2, 1) == 8) and (A(2, 2) == 9)));
 
   TinyMatrix<3, int> B(6, 5, 3, 8, 34, 6, 35, 6, 7);
+
   SECTION("checking for opposed matrix")
   {
     const TinyMatrix<3, int> minus_A = -A;
@@ -31,6 +32,7 @@ TEST_CASE("TinyMatrix", "[algebra]")
              (minus_A(1, 1) == -5) and (minus_A(1, 2) == -6) and (minus_A(2, 0) == -7) and (minus_A(2, 1) == -8) and
              (minus_A(2, 2) == -9)));
   }
+
   SECTION("checking for equality and difference tests")
   {
     const TinyMatrix<3, int> copy_A = A;
@@ -209,14 +211,24 @@ TEST_CASE("TinyMatrix", "[algebra]")
     REQUIRE(TinyMatrix<1>{}.numberOfRows() == 1);
     REQUIRE(TinyMatrix<1>{}.numberOfColumns() == 1);
     REQUIRE(TinyMatrix<1>{}.dimension() == 1);
+    REQUIRE(TinyMatrix<1>{}.numberOfValues() == 1);
 
     REQUIRE(TinyMatrix<2>{}.numberOfRows() == 2);
     REQUIRE(TinyMatrix<2>{}.numberOfColumns() == 2);
-    REQUIRE(TinyMatrix<2>{}.dimension() == 4);
+    REQUIRE(TinyMatrix<2>{}.numberOfValues() == 4);
 
     REQUIRE(TinyMatrix<3>{}.numberOfRows() == 3);
     REQUIRE(TinyMatrix<3>{}.numberOfColumns() == 3);
     REQUIRE(TinyMatrix<3>{}.dimension() == 9);
+    REQUIRE(TinyMatrix<3>{}.numberOfValues() == 9);
+  }
+
+  SECTION("is square matrix")
+  {
+    REQUIRE(TinyMatrix<1>{}.isSquare());
+    REQUIRE(TinyMatrix<2>{}.isSquare());
+    REQUIRE(TinyMatrix<3>{}.isSquare());
+    REQUIRE(TinyMatrix<4>{}.isSquare());
   }
 
   SECTION("checking for matrices output")