Use doctest as test framework

tests/doctest.cpp

@@ -0,0 +1,2 @@
+#define DOCTEST_CONFIG_IMPLEMENT_WITH_MAIN
+#include "doctest.h"

tests/test_bus.cpp

@@ -1,8 +1,9 @@
-#include <iostream>
+#include "doctest.h"
+
 #include "memory/bus.h"
 #include "memory/ram.h"
 
-int main(int argc, char** argv)
+TEST_CASE("Bus can map same device twice")
 {
   RAM r(0x1000);
   Bus b;
@@ -11,5 +12,5 @@ int main(int argc, char** argv)
   b.map_device(0x2000, 0x2FFF, &r);
 
   b.write8(0x60, 42);
-  return (b.read8(0x2060) == 42) ? 0 : 1;
+  CHECK(b.read8(0x2060) == 42);
 }

tests/test_cpu_simple.cpp

@@ -0,0 +1,27 @@
+#include "doctest.h"
+
+#include "cpu/cpu.h"
+#include "memory/ram.h"
+
+
+TEST_CASE("simple load and add")
+{
+  u8 test_ram[] = {
+    0x3E, 0x10, // LD A, $0x10
+    0x87,       // ADD A, A
+  };
+  RAM r(test_ram, 3, true);
+  Cpu cpu(&r);
+
+  CHECK(cpu.state.PC == 0x0);
+
+  cpu.step();
+
+  CHECK(cpu.state.PC == 0x2);
+  CHECK(cpu.state.A == 0x10);
+
+  cpu.step();
+
+  CHECK(cpu.state.PC == 0x3);
+  CHECK(cpu.state.A == 0x20);
+}