internal/apply/apply_test.go

@@ -1298,3 +1298,65 @@ func TestAContainerGivenNoNamesIsRunAsBefore(t *testing.T) {
 		}
 	}
 }
+
+// Defends the ordering half of novox/hq work breakdown 1.3: resources are applied in the order
+// the module declared them.
+//
+// **Already true, and untested until now** — the apply loop walks `d.Resources` and sorts nothing,
+// so a module that needs one thing before another says so by writing it first. Worth an assertion
+// because it is the kind of property a later change would break silently: sorting the resources
+// for any good reason at all — by type, by identity, for a tidier report — would still pass every
+// other test in this package.
+//
+// It is sequence, not readiness. A container started is not a container ready, and nothing here
+// waits: what depends on something being *usable* retries, which is what both example
+// provisioners do and is more robust than start ordering, because a dependency can also restart
+// long after everything was applied.
+func TestResourcesAreAppliedInTheOrderTheyWereDeclared(t *testing.T) {
+	dir := t.TempDir()
+	var order []string
+	done := map[string]bool{}
+	run := func(_ context.Context, name string, args ...string) (string, error) {
+		order = append(order, name+" "+strings.Join(args, " "))
+		// `verify` is the idempotency check, so it has to fail before the step and pass after —
+		// a stub that always succeeds means every action is already done and nothing ever runs,
+		// which is what the first version of this test measured.
+		if name == "check" {
+			if !done[args[0]] {
+				return "", fmt.Errorf("not yet")
+			}
+			return "", nil
+		}
+		done[args[0]] = true
+		return "", nil
+	}
+
+	_ = dir
+	// Trusted, because the link may not carry an action and only a bundle may (novox/hq ADR 0005).
+	// Actions are used here because they are the one shape whose execution is observable through
+	// the runner, which is what makes the order visible at all.
+	d, err := declaration.ParseTrusted([]byte(`{"declaration":1,"resources":[` +
+		`{"id":"first","type":"action","command":["step","one"],"verify":["check","one"]},` +
+		`{"id":"second","type":"action","command":["step","two"],"verify":["check","two"]},` +
+		`{"id":"third","type":"action","command":["step","three"],"verify":["check","three"]}]}`))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if _, _, err := Apply(context.Background(), archHost(t), d, store.State{},
+		store.OriginCarried, run, nil, nil); err != nil {
+		t.Fatal(err)
+	}
+
+	var ran []string
+	for _, line := range order {
+		if strings.HasPrefix(line, "step ") {
+			ran = append(ran, strings.TrimPrefix(line, "step "))
+		}
+	}
+	want := []string{"one", "two", "three"}
+	if strings.Join(ran, ",") != strings.Join(want, ",") {
+		t.Fatalf("declared one, two, three and ran %v — a module that needs one thing before "+
+			"another has no way to say so", ran)
+	}
+}