From 478f5321ad74feab86933742ea087263cb138c38 Mon Sep 17 00:00:00 2001
From: Sam Kleinman <garen@tychoish.com>
Date: Wed, 21 Jul 2021 09:54:14 -0400
Subject: [PATCH] light: run examples as integration tests (#6745)

---
 light/example_test.go |   2 -
 light/light_test.go   | 138 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 138 insertions(+), 2 deletions(-)
 create mode 100644 light/light_test.go

diff --git a/light/example_test.go b/light/example_test.go
index a542b8d3d..0fd6640c4 100644
--- a/light/example_test.go
+++ b/light/example_test.go
@@ -93,7 +93,6 @@ func ExampleClient_Update() {
 	} else {
 		fmt.Println("update failed")
 	}
-	// Output: successful update
 }
 
 // Manually getting light blocks and verifying them.
@@ -169,5 +168,4 @@ func ExampleClient_VerifyLightBlockAtHeight() {
 	}
 
 	fmt.Println("got header", h.Height)
-	// Output: got header 3
 }
diff --git a/light/light_test.go b/light/light_test.go
new file mode 100644
index 000000000..a224d71b2
--- /dev/null
+++ b/light/light_test.go
@@ -0,0 +1,138 @@
+package light_test
+
+import (
+	"context"
+	"io/ioutil"
+	"os"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+	dbm "github.com/tendermint/tm-db"
+
+	"github.com/tendermint/tendermint/abci/example/kvstore"
+	"github.com/tendermint/tendermint/libs/log"
+	"github.com/tendermint/tendermint/light"
+	"github.com/tendermint/tendermint/light/provider"
+	httpp "github.com/tendermint/tendermint/light/provider/http"
+	dbs "github.com/tendermint/tendermint/light/store/db"
+	rpctest "github.com/tendermint/tendermint/rpc/test"
+)
+
+// NOTE: these are ports of the tests from example_test.go but
+// rewritten as more conventional tests.
+
+// Automatically getting new headers and verifying them.
+func TestClientIntegration_Update(t *testing.T) {
+	t.Parallel()
+
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+	conf := rpctest.CreateConfig(t.Name())
+
+	// Start a test application
+	app := kvstore.NewApplication()
+	_, closer, err := rpctest.StartTendermint(ctx, conf, app, rpctest.SuppressStdout)
+	require.NoError(t, err)
+	defer func() { require.NoError(t, closer(ctx)) }()
+
+	// give Tendermint time to generate some blocks
+	time.Sleep(5 * time.Second)
+
+	dbDir, err := ioutil.TempDir("", "light-client-test-update-example")
+	require.NoError(t, err)
+	defer os.RemoveAll(dbDir)
+
+	chainID := conf.ChainID()
+
+	primary, err := httpp.New(chainID, conf.RPC.ListenAddress)
+	require.NoError(t, err)
+
+	block, err := primary.LightBlock(ctx, 2)
+	require.NoError(t, err)
+
+	db, err := dbm.NewGoLevelDB("light-client-db", dbDir)
+	require.NoError(t, err)
+
+	c, err := light.NewClient(
+		ctx,
+		chainID,
+		light.TrustOptions{
+			Period: 504 * time.Hour, // 21 days
+			Height: 2,
+			Hash:   block.Hash(),
+		},
+		primary,
+		[]provider.Provider{primary}, // NOTE: primary should not be used here
+		dbs.New(db),
+		light.Logger(log.TestingLogger()),
+	)
+	require.NoError(t, err)
+
+	defer func() { require.NoError(t, c.Cleanup()) }()
+
+	time.Sleep(2 * time.Second)
+
+	h, err := c.Update(ctx, time.Now())
+	require.NoError(t, err)
+	require.NotNil(t, h)
+
+	require.True(t, h.Height > 2)
+}
+
+// Manually getting light blocks and verifying them.
+func TestClientIntegration_VerifyLightBlockAtHeight(t *testing.T) {
+	t.Parallel()
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+	conf := rpctest.CreateConfig(t.Name())
+
+	// Start a test application
+	app := kvstore.NewApplication()
+
+	_, closer, err := rpctest.StartTendermint(ctx, conf, app, rpctest.SuppressStdout)
+	require.NoError(t, err)
+	defer func() { require.NoError(t, closer(ctx)) }()
+
+	// give Tendermint time to generate some blocks
+	time.Sleep(5 * time.Second)
+
+	dbDir, err := ioutil.TempDir("", "light-client-test-verify-example")
+	require.NoError(t, err)
+	defer os.RemoveAll(dbDir)
+
+	chainID := conf.ChainID()
+
+	primary, err := httpp.New(chainID, conf.RPC.ListenAddress)
+	require.NoError(t, err)
+
+	block, err := primary.LightBlock(ctx, 2)
+	require.NoError(t, err)
+
+	db, err := dbm.NewGoLevelDB("light-client-db", dbDir)
+	require.NoError(t, err)
+
+	c, err := light.NewClient(ctx,
+		chainID,
+		light.TrustOptions{
+			Period: 504 * time.Hour, // 21 days
+			Height: 2,
+			Hash:   block.Hash(),
+		},
+		primary,
+		[]provider.Provider{primary}, // NOTE: primary should not be used here
+		dbs.New(db),
+		light.Logger(log.TestingLogger()),
+	)
+	require.NoError(t, err)
+
+	defer func() { require.NoError(t, c.Cleanup()) }()
+
+	_, err = c.VerifyLightBlockAtHeight(ctx, 3, time.Now())
+	require.NoError(t, err)
+
+	h, err := c.TrustedLightBlock(3)
+	require.NoError(t, err)
+
+	require.EqualValues(t, 3, h.Height)
+}