Test internal/drawstate and the module packages each package may import

internal/drawstate/drawstate_test.go

@@ -0,0 +1,40 @@
+package drawstate
+
+import "testing"
+
+func TestOneSeedDrawsOneSequence(t *testing.T) {
+	a, b := New(42), New(42)
+	for i := 0; i < 50; i++ {
+		if x, y := a.Uint64(), b.Uint64(); x != y {
+			t.Fatalf("seed 42 diverged at draw %d: %d != %d", i, x, y)
+		}
+	}
+}
+
+func TestTwoSeedsDrawTwoSequences(t *testing.T) {
+	a, b := New(1), New(2)
+	for i := 0; i < 50; i++ {
+		if a.Uint64() != b.Uint64() {
+			return
+		}
+	}
+	t.Fatal("seeds 1 and 2 drew identical sequences")
+}
+
+func TestCountersCountFromOneEach(t *testing.T) {
+	s := New(1)
+	for want := uint64(1); want <= 3; want++ {
+		if got := s.Next(""); got != want {
+			t.Fatalf("Next(\"\") = %d, want %d", got, want)
+		}
+	}
+	if got := s.Next("orders"); got != 1 {
+		t.Fatalf("Next(orders) = %d, want its own count from 1", got)
+	}
+	if got := s.Next(""); got != 4 {
+		t.Fatalf("Next(\"\") after Next(orders) = %d, want 4", got)
+	}
+	if got := New(1).Next(""); got != 1 {
+		t.Fatalf("a new state's Next = %d, want 1", got)
+	}
+}