v0.1 - initial commit

cyclic_test.go

@@ -0,0 +1,52 @@
+package winpwn
+
+import "testing"
+
+// TestCyclicMatchesPwntools pins Cyclic(20) against pwntools' own
+// cyclic(20) output (b'aaaabaaacaaadaaaeaaa') -- if this ever drifts, every
+// offset a player calculates by hand using pwntools docs/muscle memory
+// would silently be wrong.
+func TestCyclicMatchesPwntools(t *testing.T) {
+	got := string(Cyclic(20))
+	want := "aaaabaaacaaadaaaeaaa"
+	if got != want {
+		t.Fatalf("Cyclic(20) = %q, want %q", got, want)
+	}
+}
+
+func TestCyclicFindRoundTrip(t *testing.T) {
+	buf := Cyclic(200)
+	for _, off := range []int{0, 4, 17, 100, 196} {
+		sub := buf[off : off+4]
+		if got := CyclicFind(sub); got != off {
+			t.Errorf("CyclicFind(%q) = %d, want %d", sub, got, off)
+		}
+	}
+}
+
+func TestCyclicFindNotFound(t *testing.T) {
+	if got := CyclicFind([]byte{0, 1, 2, 3}); got != -1 {
+		t.Errorf("CyclicFind(non-alphabet bytes) = %d, want -1", got)
+	}
+}
+
+// TestCyclicN8StaysBounded guards against eagerly materializing the full
+// de Bruijn period (26^8 ~ 2*10^11 bytes) when only a small prefix is
+// requested -- a real bug caught in this package's own test run (OOM
+// crash) before deBruijnEach was made to stop early via its yield callback.
+func TestCyclicN8StaysBounded(t *testing.T) {
+	buf := CyclicN(64, 8)
+	if len(buf) != 64 {
+		t.Fatalf("CyclicN(64, 8) returned %d bytes, want 64", len(buf))
+	}
+	sub := buf[16:24]
+	if off := CyclicFindN(sub, 8); off != 16 {
+		t.Errorf("CyclicFindN = %d, want 16", off)
+	}
+}
+
+func TestCyclicNZeroLength(t *testing.T) {
+	if got := CyclicN(0, 4); len(got) != 0 {
+		t.Errorf("CyclicN(0, 4) = %v, want empty", got)
+	}
+}