test(runway): end-to-end coverage for the merge queue round trip

submitqueue/core/fakemarker/BUILD.bazel → platform/fakemarker/BUILD.bazel

@@ -3,7 +3,7 @@ load("@rules_go//go:def.bzl", "go_library", "go_test")
 go_library(
     name = "go_default_library",
     srcs = ["fakemarker.go"],
-    importpath = "github.com/uber/submitqueue/submitqueue/core/fakemarker",
+    importpath = "github.com/uber/submitqueue/platform/fakemarker",
     visibility = ["//visibility:public"],
     deps = ["//platform/base/change:go_default_library"],
 )

runway/extension/merger/fake/BUILD.bazel

@@ -0,0 +1,29 @@
+load("@rules_go//go:def.bzl", "go_library", "go_test")
+
+go_library(
+    name = "go_default_library",
+    srcs = ["fake.go"],
+    importpath = "github.com/uber/submitqueue/runway/extension/merger/fake",
+    visibility = ["//visibility:public"],
+    deps = [
+        "//api/runway/messagequeue:go_default_library",
+        "//api/runway/messagequeue/protopb:go_default_library",
+        "//platform/fakemarker:go_default_library",
+        "//runway/extension/merger:go_default_library",
+    ],
+)
+
+go_test(
+    name = "go_default_test",
+    srcs = ["fake_test.go"],
+    embed = [":go_default_library"],
+    deps = [
+        "//api/base/change/protopb:go_default_library",
+        "//api/base/mergestrategy/protopb:go_default_library",
+        "//api/runway/messagequeue:go_default_library",
+        "//api/runway/messagequeue/protopb:go_default_library",
+        "//runway/extension/merger:go_default_library",
+        "@com_github_stretchr_testify//assert:go_default_library",
+        "@com_github_stretchr_testify//require:go_default_library",
+    ],
+)

runway/extension/merger/fake/fake.go

@@ -0,0 +1,115 @@
+// Copyright (c) 2025 Uber Technologies, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package fake provides a merger.Merger whose outcome is driven by the request
+// payload. With no marker it succeeds like the noop merger, behaving as a
+// best-case stub for wiring and baselines. A failure can be injected end-to-end
+// (e.g. from an e2e merge request) by embedding a marker token in a change URI
+// of the form "sq-fake=<token>":
+//
+//	sq-fake=merge-conflict -> merger.ErrConflict
+//	sq-fake=merge-invalid  -> merger.ErrInvalidRequest
+//	sq-fake=merge-error    -> a plain (non-retryable) error
+//
+// The first token found across the request's steps, in order, decides the
+// outcome for the whole request. This lets a single running stack exercise
+// Runway's terminal-failure and dead-letter paths purely by varying request
+// payloads. It is intended for examples and tests only, never production.
+package fake
+
+import (
+	"context"
+	"fmt"
+	"sync/atomic"
+
+	runwaymq "github.com/uber/submitqueue/api/runway/messagequeue"
+	runwaypb "github.com/uber/submitqueue/api/runway/messagequeue/protopb"
+	"github.com/uber/submitqueue/platform/fakemarker"
+	"github.com/uber/submitqueue/runway/extension/merger"
+)
+
+// Recognized marker tokens. See the package doc for the convention.
+const (
+	tokenConflict = "merge-conflict"
+	tokenInvalid  = "merge-invalid"
+	tokenError    = "merge-error"
+)
+
+var _ merger.Merger = (*Merger)(nil)
+
+// Merger is a Merger that succeeds unless a marker token in a change URI
+// requests otherwise.
+type Merger struct {
+	seq atomic.Uint64
+}
+
+// New returns a Merger that defaults to success and honors marker tokens
+// embedded in change URIs.
+func New() *Merger { return &Merger{} }
+
+// CheckMergeability reports the request as mergeable unless a recognized marker
+// token asks for a failure. Outputs are empty, as for any dry run.
+func (m *Merger) CheckMergeability(_ context.Context, req *runwaymq.MergeRequest) (*runwaymq.MergeResult, error) {
+	if err := injectedFailure(req); err != nil {
+		return nil, err
+	}
+
+	steps := make([]*runwaymq.StepResult, len(req.GetSteps()))
+	for i, s := range req.GetSteps() {
+		steps[i] = &runwaymq.StepResult{StepId: s.GetStepId()}
+	}
+	return &runwaymq.MergeResult{
+		Id:      req.GetId(),
+		Outcome: runwaypb.Outcome_SUCCEEDED,
+		Steps:   steps,
+	}, nil
+}
+
+// Merge reports the request as merged unless a recognized marker token asks for
+// a failure, producing one synthetic revision id per step.
+func (m *Merger) Merge(_ context.Context, req *runwaymq.MergeRequest) (*runwaymq.MergeResult, error) {
+	if err := injectedFailure(req); err != nil {
+		return nil, err
+	}
+
+	steps := make([]*runwaymq.StepResult, len(req.GetSteps()))
+	for i, s := range req.GetSteps() {
+		n := m.seq.Add(1)
+		steps[i] = &runwaymq.StepResult{
+			StepId:  s.GetStepId(),
+			Outputs: []*runwaymq.StepOutput{{Id: fmt.Sprintf("%040x", n)}},
+		}
+	}
+	return &runwaymq.MergeResult{
+		Id:      req.GetId(),
+		Outcome: runwaypb.Outcome_SUCCEEDED,
+		Steps:   steps,
+	}, nil
+}
+
+// injectedFailure returns the error the request's marker token asks for, or nil
+// when no step carries a recognized token.
+func injectedFailure(req *runwaymq.MergeRequest) error {
+	for _, s := range req.GetSteps() {
+		switch fakemarker.Token(s.GetChange().GetUris()) {
+		case tokenConflict:
+			return fmt.Errorf("fake: marked conflicting on step %s: %w", s.GetStepId(), merger.ErrConflict)
+		case tokenInvalid:
+			return fmt.Errorf("fake: marked invalid on step %s: %w", s.GetStepId(), merger.ErrInvalidRequest)
+		case tokenError:
+			return fmt.Errorf("fake: marked failing on step %s", s.GetStepId())
+		}
+	}
+	return nil
+}

runway/extension/merger/fake/fake_test.go

@@ -0,0 +1,151 @@
+// Copyright (c) 2025 Uber Technologies, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package fake
+
+import (
+	"context"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	changepb "github.com/uber/submitqueue/api/base/change/protopb"
+	strategypb "github.com/uber/submitqueue/api/base/mergestrategy/protopb"
+	runwaymq "github.com/uber/submitqueue/api/runway/messagequeue"
+	runwaypb "github.com/uber/submitqueue/api/runway/messagequeue/protopb"
+	"github.com/uber/submitqueue/runway/extension/merger"
+)
+
+const baseURI = "github://github.example.com/uber/repo/pull/1/abcdef0123456789abcdef0123456789abcdef01"
+
+// requestWith builds a two-step request whose second step carries the given
+// URIs, so tests can prove the token is found on any step, not just the first.
+func requestWith(uris ...string) *runwaymq.MergeRequest {
+	return &runwaymq.MergeRequest{
+		Id:        "queue-a/42",
+		QueueName: "queue-a",
+		Steps: []*runwaymq.MergeStep{
+			{
+				StepId:   "queue-a/1",
+				Change:   &changepb.Change{Uris: []string{baseURI}},
+				Strategy: strategypb.Strategy_REBASE,
+			},
+			{
+				StepId:   "queue-a/2",
+				Change:   &changepb.Change{Uris: uris},
+				Strategy: strategypb.Strategy_REBASE,
+			},
+		},
+	}
+}
+
+func TestUnmarkedRequestSucceeds(t *testing.T) {
+	req := requestWith(baseURI)
+
+	t.Run("check mergeability reports no outputs", func(t *testing.T) {
+		res, err := New().CheckMergeability(context.Background(), req)
+		require.NoError(t, err)
+
+		assert.Equal(t, req.GetId(), res.GetId())
+		assert.Equal(t, runwaypb.Outcome_SUCCEEDED, res.GetOutcome())
+		require.Len(t, res.GetSteps(), 2)
+		assert.Equal(t, "queue-a/1", res.GetSteps()[0].GetStepId())
+		assert.Empty(t, res.GetSteps()[0].GetOutputs())
+		assert.Equal(t, "queue-a/2", res.GetSteps()[1].GetStepId())
+		assert.Empty(t, res.GetSteps()[1].GetOutputs())
+	})
+
+	t.Run("merge reports one output per step", func(t *testing.T) {
+		res, err := New().Merge(context.Background(), req)
+		require.NoError(t, err)
+
+		assert.Equal(t, req.GetId(), res.GetId())
+		assert.Equal(t, runwaypb.Outcome_SUCCEEDED, res.GetOutcome())
+		require.Len(t, res.GetSteps(), 2)
+		require.Len(t, res.GetSteps()[0].GetOutputs(), 1)
+		require.Len(t, res.GetSteps()[1].GetOutputs(), 1)
+		assert.NotEqual(t,
+			res.GetSteps()[0].GetOutputs()[0].GetId(),
+			res.GetSteps()[1].GetOutputs()[0].GetId(),
+			"each step should produce a distinct revision id")
+	})
+}
+
+func TestMarkedRequestFails(t *testing.T) {
+	tests := []struct {
+		name  string
+		token string
+		want  error // nil means "an error that is neither terminal sentinel"
+	}{
+		{name: "conflict", token: tokenConflict, want: merger.ErrConflict},
+		{name: "invalid", token: tokenInvalid, want: merger.ErrInvalidRequest},
+		{name: "plain error", token: tokenError, want: nil},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			req := requestWith(baseURI + "?sq-fake=" + tt.token)
+
+			for _, call := range []struct {
+				name string
+				fn   func(*runwaymq.MergeRequest) (*runwaymq.MergeResult, error)
+			}{
+				{"CheckMergeability", func(r *runwaymq.MergeRequest) (*runwaymq.MergeResult, error) {
+					return New().CheckMergeability(context.Background(), r)
+				}},
+				{"Merge", func(r *runwaymq.MergeRequest) (*runwaymq.MergeResult, error) {
+					return New().Merge(context.Background(), r)
+				}},
+			} {
+				t.Run(call.name, func(t *testing.T) {
+					res, err := call.fn(req)
+					require.Error(t, err)
+					assert.Nil(t, res)
+
+					if tt.want != nil {
+						assert.ErrorIs(t, err, tt.want)
+						assert.True(t, merger.IsTerminal(err), "sentinel failures must be terminal")
+						return
+					}
+					assert.False(t, merger.IsTerminal(err),
+						"an unmarked failure must not look terminal, so it dead-letters")
+				})
+			}
+		})
+	}
+}
+
+func TestUnrecognizedTokenSucceeds(t *testing.T) {
+	req := requestWith(baseURI + "?sq-fake=some-other-fakes-token")
+
+	res, err := New().Merge(context.Background(), req)
+	require.NoError(t, err)
+	assert.Equal(t, runwaypb.Outcome_SUCCEEDED, res.GetOutcome())
+}
+
+func TestFirstRecognizedTokenWins(t *testing.T) {
+	req := &runwaymq.MergeRequest{
+		Id:        "queue-a/42",
+		QueueName: "queue-a",
+		Steps: []*runwaymq.MergeStep{
+			{StepId: "queue-a/1", Change: &changepb.Change{Uris: []string{baseURI + "?sq-fake=" + tokenConflict}}},
+			{StepId: "queue-a/2", Change: &changepb.Change{Uris: []string{baseURI + "?sq-fake=" + tokenInvalid}}},
+		},
+	}
+
+	_, err := New().Merge(context.Background(), req)
+	require.Error(t, err)
+	assert.ErrorIs(t, err, merger.ErrConflict)
+	assert.NotErrorIs(t, err, merger.ErrInvalidRequest)
+}

service/runway/server/BUILD.bazel

@@ -28,6 +28,7 @@ go_library(
         "//runway/controller/merge:go_default_library",
         "//runway/controller/mergeconflictcheck:go_default_library",
         "//runway/extension/merger:go_default_library",
+        "//runway/extension/merger/fake:go_default_library",
         "//runway/extension/merger/git:go_default_library",
         "//runway/extension/merger/noop:go_default_library",
         "@com_github_go_sql_driver_mysql//:go_default_library",

service/runway/server/docker-compose.yml

@@ -43,6 +43,10 @@ services:
       - "8080" # Random ephemeral port to avoid conflicts
     environment:
       - PORT=:8080
+      # Merger implementation. Empty (the default) resolves from the merge
+      # environment: git when MERGE_CHECKOUT_PATH is set, noop otherwise. The
+      # e2e suite sets SQ_RUNWAY_MERGER=fake to drive outcomes from the payload.
+      - MERGER=${SQ_RUNWAY_MERGER:-}
       # Queue infrastructure connection
       - QUEUE_MYSQL_DSN=root:root@tcp(mysql-queue:3306)/submitqueue?parseTime=true
       - HOSTNAME=runway-dev

service/runway/server/main.go

@@ -47,6 +47,7 @@ import (
 	"github.com/uber/submitqueue/runway/controller/merge"
 	"github.com/uber/submitqueue/runway/controller/mergeconflictcheck"
 	"github.com/uber/submitqueue/runway/extension/merger"
+	"github.com/uber/submitqueue/runway/extension/merger/fake"
 	gitmerger "github.com/uber/submitqueue/runway/extension/merger/git"
 	"github.com/uber/submitqueue/runway/extension/merger/noop"
 	"go.uber.org/zap"
@@ -302,11 +303,27 @@ func run() error {
 	return err
 }
 
-// newMergerFactory returns a merger.Factory for the server. When
-// MERGE_CHECKOUT_PATH is set it wires the git-backed merger built from the
-// MERGE_* / GIT_* environment; otherwise it falls back to the noop merger so
-// local development and compose runs need no git checkout.
+// newMergerFactory returns a merger.Factory for the server. MERGER selects the
+// implementation explicitly; when it is unset the choice falls back to the merge
+// environment — MERGE_CHECKOUT_PATH wires the git-backed merger built from the
+// MERGE_* / GIT_* environment, and its absence wires the noop merger so local
+// development and compose runs need no git checkout.
 func newMergerFactory(logger *zap.Logger, scope tally.Scope) (merger.Factory, error) {
+	switch impl := strings.ToLower(strings.TrimSpace(os.Getenv("MERGER"))); impl {
+	case "fake":
+		// Marker-driven outcomes, for e2e tests that need Runway to fail on
+		// demand without a git checkout. Never production.
+		logger.Info("MERGER=fake; using marker-driven fake merger")
+		return &fakeMergerFactory{merger: fake.New()}, nil
+	case "noop":
+		logger.Info("MERGER=noop; using noop merger")
+		return &noopMergerFactory{}, nil
+	case "", "git":
+		// Fall through to the merge-environment default below.
+	default:
+		return nil, fmt.Errorf("invalid MERGER %q", impl)
+	}
+
 	checkoutPath := os.Getenv("MERGE_CHECKOUT_PATH")
 	if checkoutPath == "" {
 		logger.Info("MERGE_CHECKOUT_PATH not set; using noop merger")
@@ -369,6 +386,16 @@ func (f *noopMergerFactory) For(_ merger.Config) (merger.Merger, error) {
 	return noop.New(), nil
 }
 
+// fakeMergerFactory shares one fake merger across queues so the synthetic
+// revision ids it mints stay unique for the lifetime of the process.
+type fakeMergerFactory struct {
+	merger merger.Merger
+}
+
+func (f *fakeMergerFactory) For(_ merger.Config) (merger.Merger, error) {
+	return f.merger, nil
+}
+
 // parseStrategy maps the MERGE_DEFAULT_STRATEGY env value to a concrete merge
 // strategy, defaulting to REBASE when unset. DEFAULT is rejected because it
 // cannot itself be the default a step resolves to.

submitqueue/extension/buildrunner/fake/BUILD.bazel

@@ -6,8 +6,8 @@ go_library(
     importpath = "github.com/uber/submitqueue/submitqueue/extension/buildrunner/fake",
     visibility = ["//visibility:public"],
     deps = [
+        "//platform/fakemarker:go_default_library",
         "//submitqueue/core/changeset:go_default_library",
-        "//submitqueue/core/fakemarker:go_default_library",
         "//submitqueue/entity:go_default_library",
         "//submitqueue/extension/buildrunner:go_default_library",
     ],