Merge branch 'runner-uncertain-last-action' into pr-73-followups

internal/verifier/marshal.go

@@ -344,7 +344,19 @@ func lastActionFields(action *Action) []actionField {
 	point := func(x, y int) []actionField {
 		return []actionField{{key: "x", value: x}, {key: "y", value: y}}
 	}
-	fields := []actionField{{key: "kind", value: string(action.Kind)}}
+	// An action whose apply call failed is not an action that did not happen:
+	// the dispatch may have landed before the error. That is unknown, and
+	// unknown is null here for the same reason every other absence in the spec
+	// surface is, so a property decides for itself instead of being handed a
+	// "nothing happened" the runner cannot vouch for.
+	var applied any
+	if action.Applied {
+		applied = true
+	}
+	fields := []actionField{
+		{key: "kind", value: string(action.Kind)},
+		{key: "applied", value: applied},
+	}
 	if action.On != "" {
 		fields = append(fields, actionField{key: "on", value: action.On})
 	}
@@ -397,7 +409,7 @@ func objectFromFields(runtime *goja.Runtime, fields []actionField) *goja.Object
 // has no Go-side state object to read: the runner pushes this JSON into the
 // page before each extractor evaluation. A nil action encodes as JSON null,
 // the same value the goja host reports on the first step of a run and after a
-// step whose action was never applied.
+// step whose action was never dispatched.
 func EncodeLastAction(action *Action) json.RawMessage {
 	if action == nil {
 		return json.RawMessage("null")

internal/verifier/marshal_test.go

@@ -168,6 +168,7 @@ func TestLastAction_WebJSONMatchesTheGojaObject(t *testing.T) {
 	}{
 		{"nil", nil},
 		{"Tap", &Action{Kind: ActionKindTap, On: "id:TxnSubmit", X: 12, Y: 34}},
+		{"TapApplied", &Action{Kind: ActionKindTap, On: "id:TxnSubmit", Applied: true}},
 		{"TapWithoutSelector", &Action{Kind: ActionKindTap, X: 12, Y: 34}},
 		{"DoubleTap", &Action{Kind: ActionKindDoubleTap, On: `desc:say "hi" <b>`}},
 		{"InputText", &Action{Kind: ActionKindInputText, On: "id:field", Text: "50"}},
@@ -193,3 +194,42 @@ func TestLastAction_WebJSONMatchesTheGojaObject(t *testing.T) {
 		})
 	}
 }
+
+// A spec has to be able to tell three things apart: no action ran, an action
+// ran, and an action was dispatched whose fate the runner cannot vouch for.
+// The third used to be reported as the first, which is how a property that
+// reasons "an effect landed with no action to cause it" convicts an app over
+// an RPC deadline.
+func TestLastAction_SeparatesNoActionFromAnActionOfUnknownFate(t *testing.T) {
+	verifier := newVerifier(t)
+	mustLoad(t, verifier, `
+		globalThis.fate = __sanderling__.extract(state =>
+			state.lastAction === null ? "no action"
+			: state.lastAction.applied === true ? "applied"
+			: state.lastAction.applied === null ? "unknown"
+			: "unreadable");
+	`)
+
+	for _, testCase := range []struct {
+		name   string
+		action *Action
+		want   string
+	}{
+		{"nothing ran", nil, "no action"},
+		{"dispatch confirmed", &Action{Kind: ActionKindTap, On: "id:TxnSubmit", Applied: true}, "applied"},
+		{"dispatch unconfirmed", &Action{Kind: ActionKindTap, On: "id:TxnSubmit"}, "unknown"},
+	} {
+		t.Run(testCase.name, func(t *testing.T) {
+			if err := verifier.PushSnapshot(SnapshotInput{
+				Snapshots:  Snapshots{},
+				LastAction: testCase.action,
+			}); err != nil {
+				t.Fatal(err)
+			}
+			handle := verifier.runtime.GlobalObject().Get("fate").ToObject(verifier.runtime)
+			if got := handle.Get("current").String(); got != testCase.want {
+				t.Errorf("the spec read %q, want %q", got, testCase.want)
+			}
+		})
+	}
+}

internal/verifier/types.go

@@ -33,6 +33,11 @@ type Action struct {
 	// Direction is the scroll direction for ActionKindScroll: one of "up",
 	// "down", "left", "right". Empty for every other kind.
 	Direction string
+	// Applied is meaningful only on the action a step reports to the spec as
+	// state.lastAction: true when the runner saw the dispatch succeed, false
+	// when the apply call failed and nothing can say whether the action
+	// reached the app. The spec is told which of the two it is.
+	Applied bool
 }
 
 // LogEntry mirrors a logcat line captured between steps.