writing-e2e-tests

name	writing-e2e-tests
description	Use when creating, modifying, or reviewing E2E tests in pkg/e2e/tests/. Triggers on "e2e test", "add e2e test", "new e2e test", or when working with files under pkg/e2e/tests/.

Writing E2E Tests

Overview

E2E tests live in pkg/e2e/tests/ and implement the types.Test interface. Each test gets a fully isolated Environment with its own Docker network, Anvil chain, Redis, toxiproxy, and containers. The runner handles all setup/teardown.

Creating a New Test

Step 1: Create the test file

Create pkg/e2e/tests/<snake_case_name>.go implementing types.Test:

package tests

import (
    "context"
    "time"

    "github.com/stretchr/testify/require"
    "github.com/xmtp/xmtpd/pkg/e2e/types"
)

type MyTest struct{}

func NewMyTest() *MyTest { return &MyTest{} }

func (t *MyTest) Name() string        { return "my-test" }
func (t *MyTest) Description() string { return "One-line description of what this verifies" }

func (t *MyTest) Run(ctx context.Context, env *types.Environment) error {
    require := require.New(env.T())

    // 1. Set up infrastructure
    require.NoError(env.AddNode(ctx))
    require.NoError(env.AddNode(ctx))
    require.NoError(env.AddGateway(ctx))

    // 2. Create clients and generate traffic
    require.NoError(env.NewClient(100))
    require.NoError(env.Client(100).PublishEnvelopes(ctx, 10))

    // 3. Assert with timeouts
    checkCtx, cancel := context.WithTimeout(ctx, 60*time.Second)
    defer cancel()
    for _, n := range env.Nodes() {
        require.NoError(n.WaitForEnvelopes(checkCtx, 1))
    }

    return nil
}

var _ types.Test = (*MyTest)(nil)

Step 2: Register the test

Add the constructor to pkg/e2e/runner/registry.go:

func AllTests() []types.Test {
    return []types.Test{
        // ... existing tests ...
        tests.NewMyTest(),
    }
}

Step 3: Lint and verify

Run dev/lint-fix to ensure the code passes all linters.

Conventions

File and naming

• File name: snake_case.go matching the test name (e.g. chaos_node_down.go for "chaos-node-down")
• Struct name: PascalCase + Test suffix (e.g. ChaosNodeDownTest)
• Constructor: NewXxxTest() returning a pointer
• Name() returns a kebab-case identifier (e.g. "chaos-node-down")
• Description() returns a short, human-readable sentence (no period)
• Add compile-time interface check: var _ types.Test = (*MyTest)(nil)

Test structure pattern

Every test follows this structure:

1. Infrastructure setup -- env.AddNode(ctx), env.AddGateway(ctx)
2. Client creation -- env.NewClient(nodeID)
3. Action -- publish traffic, inject chaos, stop/start nodes, etc.
4. Assertion with timeout -- always wrap waits in context.WithTimeout
5. Cleanup (optional) -- stop traffic generators, remove toxics

Assertions

• Use require := require.New(env.T()) for fatal assertions (stops test on failure)
• Use assert := assert.New(env.T()) for non-fatal checks (continues after failure)
• Prefer require for setup steps (AddNode, AddGateway, NewClient)
• Include descriptive messages: require.NoError(err, "failed to do X for node %d", nodeID)

Timeouts

• Always wrap polling waits in context.WithTimeout -- never wait indefinitely
• Short operations (envelope replication): 30-60 seconds
• Payer report creation (depends on worker scheduling): up to 65 minutes
• Post-generator operations (attestation, submission): 10-15 minutes
• Use ctx (the test's parent context) as the parent for all timeouts

Logging

• Use env.Logger for structured logging (zap)
• Log phase transitions: env.Logger.Info("phase N: description")
• Log important state: balances, counts, node IDs
• Use zap fields, not string formatting: zap.Uint32("node_id", id)

Available API

See pkg/e2e/README.md for the full API reference.

Quick reference

// Node management
env.AddNode(ctx)                              // register on-chain + start container
env.AddNode(ctx, types.WithAlias("name"))     // custom alias
env.AddNode(ctx, types.WithNodeImage("img"))  // custom image
env.AddNode(ctx, types.WithNodeEnvVars(m))    // extra env vars
env.Node(100)                                 // access by on-chain ID
env.Nodes()                                   // all nodes

// Gateway management
env.AddGateway(ctx)
env.AddGateway(ctx, types.WithGatewayAlias("name"))
env.Gateway(0)                                // access by creation index
env.Gateways()

// Client management
env.NewClient(100)                            // create client for node 100
env.NewClient(200, types.WithPayerKey(key))   // custom payer key
env.Client(100)                               // access by node ID
env.Clients()

// NodeHandle -- lifecycle
node.Stop(ctx)
node.Start(ctx)

// NodeHandle -- on-chain
node.AddToCanonicalNetwork(ctx)
node.RemoveFromCanonicalNetwork(ctx)

// NodeHandle -- chaos (requires toxiproxy)
node.AddLatency(ctx, ms)
node.AddBandwidthLimit(ctx, kbps)
node.AddConnectionReset(ctx, timeoutMs)
node.AddTimeout(ctx, timeoutMs)               // 0 = black hole
node.RemoveAllToxics(ctx)

// NodeHandle -- observation
node.GetEnvelopeCount(ctx)
node.GetVectorClock(ctx)
node.GetStagedEnvelopeCount(ctx)
node.GetPayerReportCount(ctx)
node.GetPayerReportStatusCounts(ctx)
node.GetUnsettledUsage(ctx)
node.GetSettledPayerReports(ctx)
node.WaitForEnvelopes(ctx, minCount)
node.WaitForPayerReports(ctx, checkFn, description)

// NodeHandle -- balances
node.GetFeeTokenBalance(ctx)
node.GetGasBalance(ctx)

// GatewayHandle
gw.Stop(ctx)
gw.Deposit(ctx, amount)
gw.RequestWithdrawal(ctx, amount)
gw.GetPayerBalance(ctx)

// ClientHandle -- traffic
client.PublishEnvelopes(ctx, count)
client.GenerateTraffic(ctx, client.TrafficOptions{BatchSize: 10, Duration: 5*time.Minute})
client.Stop()

// ClientHandle -- payer ops
client.Deposit(ctx, amount)
client.GetPayerBalance(ctx)
client.RequestWithdrawal(ctx, amount)

// Environment -- on-chain operations
env.UpdateRates(ctx, types.RateOptions{...})
env.FundPayer(ctx, address, amount)
env.MintFeeToken(ctx, amount)
env.DepositPayer(ctx, address, amount)
env.GetPayerBalance(ctx, address)
env.GetFeeTokenBalance(ctx, address)
env.GetGasBalance(ctx, address)
env.SendExcessToFeeDistributor(ctx)
env.GetPayerRegistryExcess(ctx)
env.ClaimFromDistributionManager(ctx, ownerKey, nodeID, originatorIDs, indices)
env.WithdrawFromDistributionManager(ctx, ownerKey, nodeID)

Common Patterns

Verify replication across all nodes

checkCtx, cancel := context.WithTimeout(ctx, 60*time.Second)
defer cancel()
for _, n := range env.Nodes() {
    require.NoError(n.WaitForEnvelopes(checkCtx, expectedCount))
}

Chaos: stop and restart a node

node := env.Node(200)
require.NoError(node.Stop(ctx))
// ... do something while node is down ...
require.NoError(node.Start(ctx))
// ... verify recovery ...

Chaos: inject and remove latency

require.NoError(node.AddLatency(ctx, 500))
// ... traffic while latency is active ...
require.NoError(node.RemoveAllToxics(ctx))
// ... verify recovery ...

Background traffic with cleanup

env.Client(100).GenerateTraffic(ctx, client.TrafficOptions{
    BatchSize: 10,
    Duration:  5 * time.Minute,
})
defer env.Client(100).Stop()

Fund a payer and verify deposit

amount := new(big.Int).Exp(big.NewInt(10), big.NewInt(18), nil) // 1e18
require.NoError(env.Client(100).Deposit(ctx, amount))
balance, err := env.Client(100).GetPayerBalance(ctx)
require.NoError(err)
require.Positive(balance.Sign())

Wait for payer report status

require.NoError(node.WaitForPayerReports(
    ctx,
    func(c *observe.PayerReportStatusCounts) bool {
        return c.SubmissionSettled > 0
    },
    "at least 1 settled payer report",
))

Node IDs

Nodes are assigned IDs 100, 200, 300, etc. in creation order. After calling env.AddNode(ctx) three times, you have nodes 100, 200, and 300. Use these IDs consistently when creating clients: env.NewClient(100) creates a client that publishes to node 100.