promptkit/configuration_diff_contract_test.go

package promptkit_test

import (
	"errors"
	"strings"
	"testing"

	"go.maximumdirect.net/configkit"
	"go.maximumdirect.net/promptkit"
)

func TestConfigurationInspectionDiffsCapturedValues(t *testing.T) {
	left := comparisonInspection(t, "earlier-model")
	right := comparisonInspection(t, "later-model")

	differences, err := left.Diff(right)
	if err != nil {
		t.Fatalf("compare captured configurations: %v", err)
	}
	if len(differences) != 1 {
		t.Fatalf("difference count = %d, want 1: %+v", len(differences), differences)
	}
	difference := differences[0]
	if got, want := difference.Path.String(), "/profiles"; got != want {
		t.Fatalf("difference path = %q, want %q", got, want)
	}
	if !strings.Contains(difference.Left.YAML, "earlier-model") || !strings.Contains(difference.Right.YAML, "later-model") {
		t.Fatalf("difference snapshots = (%q, %q)", difference.Left.YAML, difference.Right.YAML)
	}

	reversed, err := right.Diff(left)
	if err != nil {
		t.Fatalf("compare reversed configurations: %v", err)
	}
	if len(reversed) != 1 || reversed[0].Path.String() != difference.Path.String() ||
		!strings.Contains(reversed[0].Left.YAML, "later-model") ||
		!strings.Contains(reversed[0].Right.YAML, "earlier-model") {
		t.Fatalf("reversed difference = %+v", reversed)
	}

	equal := comparisonInspection(t, "earlier-model")
	if equal, err := left.Diff(equal); err != nil || len(equal) != 0 {
		t.Fatalf("compare equal configurations = (%+v, %v), want no differences", equal, err)
	}
	if equal, err := left.Diff(left); err != nil || len(equal) != 0 {
		t.Fatalf("compare view with itself = (%+v, %v), want no differences", equal, err)
	}
}

func TestConfigurationInspectionDiffRejectsZeroViews(t *testing.T) {
	valid := comparisonInspection(t, "current-model")
	var zero promptkit.ConfigurationInspection

	for _, comparison := range []struct {
		name        string
		left, right promptkit.ConfigurationInspection
	}{
		{name: "zero left", left: zero, right: valid},
		{name: "zero right", left: valid, right: zero},
		{name: "both zero", left: zero, right: zero},
	} {
		t.Run(comparison.name, func(t *testing.T) {
			differences, err := comparison.left.Diff(comparison.right)
			if !errors.Is(err, promptkit.ErrInvalidConfig) || len(differences) != 0 {
				t.Fatalf("Diff() = (%+v, %v), want ErrInvalidConfig and no records", differences, err)
			}
		})
	}
}

func TestConfigurationInspectionDiffIgnoresSourceHistory(t *testing.T) {
	left := comparisonInspectionFrom(t, "earlier source", "same-model", nil)
	right := comparisonInspectionFrom(t, "later source", "same-model", nil)
	if !hasSourceLabel(left, "earlier source") || !hasSourceLabel(right, "later source") {
		t.Fatal("comparison fixtures did not retain their distinct source labels")
	}

	differences, err := left.Diff(right)
	if err != nil || len(differences) != 0 {
		t.Fatalf("compare equal effective values with different sources = (%+v, %v), want no differences", differences, err)
	}
}

func TestConfigurationInspectionDiffReportsPresenceAndSequences(t *testing.T) {
	left := comparisonInspectionFrom(t, "before", "same-model", map[string]any{
		"sequence": []any{"earlier", "unchanged"},
	})
	right := comparisonInspectionFrom(t, "after", "same-model", map[string]any{
		"nullable": nil,
		"sequence": []any{"later", "unchanged"},
	})

	differences, err := left.Diff(right)
	if err != nil {
		t.Fatalf("compare presence and sequence values: %v", err)
	}
	if len(differences) != 1 || differences[0].Path.String() != "/backends" {
		t.Fatalf("atomic backend list difference = %+v", differences)
	}
	difference := differences[0]
	if !difference.Left.Present || !difference.Right.Present ||
		strings.Contains(difference.Left.YAML, "nullable:") || !strings.Contains(difference.Right.YAML, "nullable: null") ||
		!strings.Contains(difference.Left.YAML, "earlier") || !strings.Contains(difference.Right.YAML, "later") {
		t.Fatalf("atomic sequence snapshots = %+v", difference)
	}
}

func TestConfigurationInspectionDiffProtectsSensitiveValuesAndReturnedRecords(t *testing.T) {
	left := comparisonInspectionFrom(t, "before", "same-model", map[string]any{
		"token":   "left-secret-sentinel",
		"visible": "before-value",
	})
	right := comparisonInspectionFrom(t, "after", "same-model", map[string]any{
		"token":   "right-secret-sentinel",
		"visible": "after-value",
	})

	differences, err := left.Diff(right)
	if err != nil {
		t.Fatalf("compare sensitive values: %v", err)
	}
	if len(differences) != 1 || differences[0].Path.String() != "/backends" {
		t.Fatalf("sensitive backend list difference = %+v", differences)
	}
	secret := differences[0]
	if !secret.Left.Redacted || !secret.Right.Redacted || !secret.HiddenChanged {
		t.Fatalf("sensitive difference = %+v", secret)
	}
	if strings.Contains(secret.Left.YAML, "left-secret-sentinel") || strings.Contains(secret.Left.YAML, "right-secret-sentinel") ||
		strings.Contains(secret.Right.YAML, "left-secret-sentinel") || strings.Contains(secret.Right.YAML, "right-secret-sentinel") {
		t.Fatalf("sensitive snapshots disclosed a value: %+v", secret)
	}
	if !strings.Contains(secret.Left.YAML, "before-value") || !strings.Contains(secret.Right.YAML, "after-value") {
		t.Fatalf("public sibling missing from snapshots: %+v", secret)
	}

	differences[0].Path = configkit.Keys("caller", "mutation")
	differences[0].Left.YAML = "caller mutation"
	differences[0].Right.YAML = "caller mutation"
	again, err := left.Diff(right)
	if err != nil {
		t.Fatalf("repeat comparison after mutating returned records: %v", err)
	}
	if len(again) != 1 {
		t.Fatalf("repeat difference count = %d, want 1: %+v", len(again), again)
	}
	againByPath := differencesByPath(again)
	if _, exists := againByPath["/caller/mutation"]; exists {
		t.Fatal("mutating returned path reached retained inspection")
	}
	if _, exists := againByPath["/backends"]; !exists {
		t.Fatalf("original backend path was lost after mutation: %+v", again)
	}
	for _, difference := range again {
		if difference.Left.YAML == "caller mutation" || difference.Right.YAML == "caller mutation" {
			t.Fatalf("mutating returned snapshots reached retained inspection: %+v", difference)
		}
	}
}

func TestConfigurationInspectionDiffMasksSensitiveShapeReplacement(t *testing.T) {
	left := comparisonInspectionFrom(t, "before", "same-model", map[string]any{
		"details": map[string]any{
			"token": "nested-secret-sentinel",
			"label": "public detail",
		},
	})
	right := comparisonInspectionFrom(t, "after", "same-model", map[string]any{
		"details": "replacement",
	})

	differences, err := left.Diff(right)
	if err != nil {
		t.Fatalf("compare sensitive shape replacement: %v", err)
	}
	if len(differences) != 1 || differences[0].Path.String() != "/backends" {
		t.Fatalf("shape replacement differences = %+v", differences)
	}
	difference := differences[0]
	if !difference.Left.Redacted || !difference.Right.Redacted || !difference.HiddenChanged {
		t.Fatalf("shape replacement masking = %+v", difference)
	}
	if strings.Contains(difference.Left.YAML, "nested-secret-sentinel") || strings.Contains(difference.Right.YAML, "nested-secret-sentinel") {
		t.Fatalf("shape replacement disclosed a sensitive value: %+v", difference)
	}
}

func comparisonInspection(t *testing.T, model string) promptkit.ConfigurationInspection {
	t.Helper()
	return comparisonInspectionFrom(t, "comparison fixture", model, nil)
}

func comparisonInspectionFrom(t *testing.T, source, model string, extraParams map[string]any) promptkit.ConfigurationInspection {
	t.Helper()
	backend := map[string]any{"id": "local", "endpoint": "https://example.invalid/v1"}
	if extraParams != nil {
		backend["extra_params"] = extraParams
	}
	engine, err := promptkit.NewEngine(promptkit.Config{Sources: promptkit.ConfigurationSources{
		Underlays: []configkit.Underlay{{Inputs: []configkit.Input{{Source: configkit.Mapping(source, map[string]any{
			"backends": []any{backend},
			"profiles": []any{map[string]any{
				"id": "offline", "backend": "local",
				"model": model,
			}},
		})}}}},
	}})
	if err != nil {
		t.Fatalf("construct comparison engine: %v", err)
	}
	inspection, err := engine.InspectConfiguration()
	if err != nil {
		t.Fatalf("inspect comparison engine: %v", err)
	}
	return inspection
}

func differencesByPath(differences []configkit.Difference) map[string]configkit.Difference {
	byPath := make(map[string]configkit.Difference, len(differences))
	for _, difference := range differences {
		byPath[difference.Path.String()] = difference
	}
	return byPath
}

func hasSourceLabel(view promptkit.ConfigurationInspection, label string) bool {
	for _, source := range view.Sources() {
		if source.Label == label {
			return true
		}
	}
	return false
}