1 files changed, 115 insertions, 0 deletions
diff --git a/tests/cart_test.go b/tests/cart_test.go
new file mode 100644
index 0000000..5b41007
--- /dev/null
+++ b/tests/cart_test.go
@@ -0,0 +1,115 @@
+package tests
+
+import (
+	"crecher.net/gones/v2/cart"
+	"os"
+	"testing"
+)
+
+const nestestPath = "testdata/nestest.nes"
+
+func header(prgBanks, chrBanks, flags6, flags7 byte) []byte {
+	h := make([]byte, 16, 16+int(prgBanks)*16*1024+int(chrBanks)*8*1024)
+	copy(h, "NES\x1A")
+	h[4], h[5], h[6], h[7] = prgBanks, chrBanks, flags6, flags7
+	h = append(h, make([]byte, int(prgBanks)*16*1024)...)
+	h = append(h, make([]byte, int(chrBanks)*8*1024)...)
+	return h
+}
+
+func TestNestestHeader(t *testing.T) {
+	raw, err := os.ReadFile(nestestPath)
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Logf("header: % x", raw[:16])
+
+	c, err := cart.Parse(raw)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if want := (raw[6] >> 4) | (raw[7] & 0xF0); c.MapperID != want {
+		t.Errorf("MapperID = %d, want %d", c.MapperID, want)
+	}
+	if c.MapperID != 0 {
+		t.Errorf("nestest should be mapper 0, got %d", c.MapperID)
+	}
+	if want := int(raw[4]) * 16 * 1024; len(c.PRG) != want {
+		t.Errorf("len(PRG) = %d, want %d", len(c.PRG), want)
+	}
+	if want := int(raw[5]) * 8 * 1024; len(c.CHR) != want {
+		t.Errorf("len(CHR) = %d, want %d", len(c.CHR), want)
+	}
+	wantMirror := cart.Horizontal
+	if raw[6]&0x01 != 0 {
+		wantMirror = cart.Vertical
+	}
+	if c.Mirroring != wantMirror {
+		t.Errorf("Mirroring = %v, want %v", c.Mirroring, wantMirror)
+	}
+}
+
+func TestLoadNestestResetVector(t *testing.T) {
+	c, err := cart.Load(nestestPath)
+	if err != nil {
+		t.Fatal(err)
+	}
+	lo := uint16(c.Mapper.CPURead(0xFFFC))
+	hi := uint16(c.Mapper.CPURead(0xFFFD))
+	if got := hi<<8 | lo; got != 0xC004 {
+		t.Errorf("reset vector = %#04x, want 0xC004", got)
+	}
+}
+
+func TestParseErrors(t *testing.T) {
+	tests := []struct {
+		name string
+		data []byte
+	}{
+		{"empty", nil},
+		{"shorter than header", []byte("NES\x1A")},
+		{"bad magic", append([]byte("XXXX"), make([]byte, 12)...)},
+		{"truncated PRG", header(2, 1, 0, 0)[:16+1024]},
+		{"unsupported mapper 1", header(1, 1, 0x10, 0)},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if _, err := cart.Parse(tt.data); err == nil {
+				t.Error("expected error, got nil")
+			}
+		})
+	}
+}
+
+func TestParseCHRRAM(t *testing.T) {
+	c, err := cart.Parse(header(1, 0, 0, 0))
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !c.CHRIsRAM || len(c.CHR) != 8*1024 {
+		t.Errorf("CHRIsRAM = %v, len(CHR) = %d; want true, 8192", c.CHRIsRAM, len(c.CHR))
+	}
+	c.Mapper.PPUWrite(0x0010, 0xAB)
+	if got := c.Mapper.PPURead(0x0010); got != 0xAB {
+		t.Errorf("CHR-RAM readback = %#02x, want 0xAB", got)
+	}
+}
+
+func TestParseFlags(t *testing.T) {
+	c, err := cart.Parse(header(1, 1, 0x03, 0))
+	if err != nil {
+		t.Fatal(err)
+	}
+	if c.Mirroring != cart.Vertical || !c.Battery {
+		t.Errorf("Mirroring = %v, Battery = %v; want cart.Vertical, true", c.Mirroring, c.Battery)
+	}
+
+	c, err = cart.Parse(header(1, 1, 0x09, 0))
+	if err != nil {
+		t.Fatal(err)
+	}
+	if c.Mirroring != cart.FourScreen {
+		t.Errorf("Mirroring = %v, want cart.FourScreen", c.Mirroring)
+	}
+}