WIP: restore lost C behaviors (schtick message, forced redraw, greeting)

Incomplete checkpoint, preserved after the implementing session hit a
capacity limit partway through mutation verification. NOT reviewed and NOT
gate-clean: make fmt has not been run, so fmt-check currently fails on
ARCHITECTURE.md and TODO.md.

Work still outstanding before this is fit for review:
  - run make fmt and fold the result in
  - finish mutation-proving each of the three behaviors
  - verify every message string byte-for-byte against the C sources
  - confirm TestSeedCompatItemTables passes with its golden untouched

Refs #13.

game/effects_test.go

@@ -194,6 +194,74 @@ func TestZapSlowMonster(t *testing.T) {
 	}
 }
 
+// bizarreSchtick is C's message for a zap that matched no case at all
+// (sticks.c do_zap, the "otherwise" arm). Shared by the pair of tests
+// below so that the one asserting it appears and the one asserting it
+// does not can never drift apart.
+const bizarreSchtick = "what a bizarre schtick!"
+
+// TestZapUnhandledWandSaysBizarreSchtick pins the closing arm of C's zap
+// switch. Every WS_ kind has a case, so the arm is reachable only for an
+// o_which outside the table — here a wand one past the end, the state a
+// corrupt save file can still describe. C's message is not gated on the
+// wizard flag, only on the MASTER build this port is, so no test setup
+// turns it on.
+func TestZapUnhandledWandSaysBizarreSchtick(t *testing.T) {
+	t.Parallel()
+
+	g := mkGameInput(t)
+	wand := malformed(KindWand)
+	wand.Charges = 3
+	ch := give(g, wand)
+
+	setInput(t, g, ch)
+	g.Msgs.Huh = ""
+
+	g.doZap()
+
+	if g.Msgs.Huh != bizarreSchtick {
+		t.Errorf("message = %q, want %q", g.Msgs.Huh, bizarreSchtick)
+	}
+
+	// C falls out of the switch into o_charges-- from the otherwise arm
+	// as much as from any other.
+	if wand.Charges != 2 {
+		t.Errorf("charges = %d after zapping, want 2", wand.Charges)
+	}
+}
+
+// TestZapWandOfNothingIsSilent is the other half, and the reason the
+// message cannot simply be attached to "no handler ran". WS_NOP is a case
+// of C's switch in its own right — "when WS_NOP: break;" — so the wand
+// that does nothing does it quietly, and only a kind C had no case for
+// is bizarre.
+func TestZapWandOfNothingIsSilent(t *testing.T) {
+	t.Parallel()
+
+	g := mkGameInput(t)
+	stick := newObject()
+	stick.Kind = KindWand
+	stick.Which = int(WandNothing)
+	g.fixStick(stick)
+	ch := give(g, stick)
+
+	setInput(t, g, ch)
+
+	charges := stick.Charges
+	g.Msgs.Huh = ""
+
+	g.doZap()
+
+	if g.Msgs.Huh == bizarreSchtick {
+		t.Errorf("the wand of nothing said %q; WS_NOP is a case of C's "+
+			"switch, not an unhandled kind", bizarreSchtick)
+	}
+
+	if stick.Charges != charges-1 {
+		t.Error("zap did not use a charge")
+	}
+}
+
 func TestParseOpts(t *testing.T) {
 	t.Parallel()