Add tests for increment and decrement operators

test/operators/increment_decrement.test.cpp

@@ -0,0 +1,41 @@
+#define CATCH_CONFIG_MAIN
+
+#include "constructors/constructors.hpp"
+#include "operators/assignment.hpp"
+#include "operators/increment_decrement.hpp"
+#include "operators/io_stream.hpp"
+#include "operators/relational.hpp"
+#include "third_party/catch.hpp"
+
+
+TEST_CASE("Increment operators 1", "[increment][operators]") {
+    BigInt num;
+    REQUIRE(num++ == 0);
+    REQUIRE(num == 1);
+    REQUIRE(++num == 2);
+    REQUIRE(num == 2);
+}
+
+TEST_CASE("Increment operators 2", "[increment][operators]") {
+    BigInt num = -1000000000;
+    REQUIRE(num++ == -1000000000);
+    REQUIRE(num == -999999999);
+    REQUIRE(++num == -999999998);
+    REQUIRE(num == -999999998);
+}
+
+TEST_CASE("Decrement operators 1", "[increment][operators]") {
+    BigInt num;
+    REQUIRE(num-- == 0);
+    REQUIRE(num == -1);
+    REQUIRE(--num == -2);
+    REQUIRE(num == -2);
+}
+
+TEST_CASE("Decrement operators 2", "[increment][operators]") {
+    BigInt num = -1000000000;
+    REQUIRE(num-- == -1000000000);
+    REQUIRE(num == -1000000001);
+    REQUIRE(--num == -1000000002);
+    REQUIRE(num == -1000000002);
+}