testutil: add ApplyMockIODiscardOutErr, simplify existing functions (c…

…osmos#6665)

client/cmd_test.go

@@ -3,14 +3,14 @@ package client_test
 import (
 	"context"
 	"fmt"
-	"io/ioutil"
 	"testing"
 
 	"github.com/spf13/cobra"
 	"github.com/stretchr/testify/require"
 
 	"github.com/cosmos/cosmos-sdk/client"
 	"github.com/cosmos/cosmos-sdk/client/flags"
+	"github.com/cosmos/cosmos-sdk/testutil"
 )
 
 func TestValidateCmd(t *testing.T) {
@@ -106,8 +106,7 @@ func TestSetCmdClientContextHandler(t *testing.T) {
 			ctx = context.WithValue(ctx, client.ClientContextKey, &client.Context{})
 
 			cmd := newCmd()
-			cmd.SetOut(ioutil.Discard)
-			cmd.SetErr(ioutil.Discard)
+			_ = testutil.ApplyMockIODiscardOutErr(cmd)
 			cmd.SetArgs(tc.args)
 
 			require.NoError(t, cmd.ExecuteContext(ctx))

client/keys/add_ledger_test.go

@@ -53,7 +53,7 @@ func Test_runAddCmdLedgerWithCustomCoinType(t *testing.T) {
 		fmt.Sprintf("--%s=%s", flags.FlagKeyringBackend, keyring.BackendTest),
 	})
 
-	mockIn, _, _ := testutil.ApplyMockIO(cmd)
+	mockIn := testutil.ApplyMockIODiscardOutErr(cmd)
 	mockIn.Reset("test1234\ntest1234\n")
 	require.NoError(t, cmd.Execute())
 
@@ -85,7 +85,7 @@ func Test_runAddCmdLedgerWithCustomCoinType(t *testing.T) {
 func Test_runAddCmdLedger(t *testing.T) {
 	cmd := AddKeyCommand()
 	cmd.Flags().AddFlagSet(Commands().PersistentFlags())
-	mockIn, _, _ := testutil.ApplyMockIO(cmd)
+	mockIn := testutil.ApplyMockIODiscardOutErr(cmd)
 
 	// Prepare a keybase
 	kbHome, kbCleanUp := testutil.NewTestCaseDir(t)

client/keys/add_test.go

@@ -19,7 +19,7 @@ func Test_runAddCmdBasic(t *testing.T) {
 	cmd := AddKeyCommand()
 	cmd.Flags().AddFlagSet(Commands().PersistentFlags())
 
-	mockIn, _, _ := testutil.ApplyMockIO(cmd)
+	mockIn := testutil.ApplyMockIODiscardOutErr(cmd)
 
 	kbHome, kbCleanUp := testutil.NewTestCaseDir(t)
 	require.NotNil(t, kbHome)

client/keys/delete_test.go

@@ -16,7 +16,7 @@ import (
 func Test_runDeleteCmd(t *testing.T) {
 	cmd := DeleteKeyCommand()
 	cmd.Flags().AddFlagSet(Commands().PersistentFlags())
-	mockIn, _, _ := testutil.ApplyMockIO(cmd)
+	mockIn := testutil.ApplyMockIODiscardOutErr(cmd)
 
 	yesF, _ := cmd.Flags().GetBool(flagYes)
 	forceF, _ := cmd.Flags().GetBool(flagForce)

client/keys/export_test.go

@@ -17,7 +17,7 @@ import (
 func Test_runExportCmd(t *testing.T) {
 	cmd := ExportKeyCommand()
 	cmd.Flags().AddFlagSet(Commands().PersistentFlags())
-	mockIn, _, _ := testutil.ApplyMockIO(cmd)
+	mockIn := testutil.ApplyMockIODiscardOutErr(cmd)
 
 	// Now add a temporary keybase
 	kbHome, cleanUp := testutil.NewTestCaseDir(t)

client/keys/import_test.go

@@ -17,7 +17,7 @@ import (
 func Test_runImportCmd(t *testing.T) {
 	cmd := ImportKeyCommand()
 	cmd.Flags().AddFlagSet(Commands().PersistentFlags())
-	mockIn, _, _ := testutil.ApplyMockIO(cmd)
+	mockIn := testutil.ApplyMockIODiscardOutErr(cmd)
 
 	// Now add a temporary keybase
 	kbHome, cleanUp := testutil.NewTestCaseDir(t)

client/keys/list_test.go

@@ -24,7 +24,7 @@ func Test_runListCmd(t *testing.T) {
 	kbHome2, cleanUp2 := testutil.NewTestCaseDir(t)
 	t.Cleanup(cleanUp2)
 
-	mockIn, _, _ := testutil.ApplyMockIO(cmd)
+	mockIn := testutil.ApplyMockIODiscardOutErr(cmd)
 	kb, err := keyring.New(sdk.KeyringServiceName(), keyring.BackendTest, kbHome2, mockIn)
 	require.NoError(t, err)
 

client/keys/migrate_test.go

@@ -2,7 +2,6 @@ package keys
 
 import (
 	"fmt"
-	"io/ioutil"
 	"testing"
 
 	"github.com/otiai10/copy"
@@ -16,8 +15,7 @@ import (
 
 func Test_runMigrateCmd(t *testing.T) {
 	cmd := AddKeyCommand()
-	cmd.SetErr(ioutil.Discard)
-	cmd.SetOut(ioutil.Discard)
+	_ = testutil.ApplyMockIODiscardOutErr(cmd)
 	cmd.Flags().AddFlagSet(Commands().PersistentFlags())
 
 	kbHome, kbCleanUp := testutil.NewTestCaseDir(t)
@@ -35,7 +33,7 @@ func Test_runMigrateCmd(t *testing.T) {
 
 	cmd = MigrateCommand()
 	cmd.Flags().AddFlagSet(Commands().PersistentFlags())
-	mockIn, _, _ := testutil.ApplyMockIO(cmd)
+	mockIn := testutil.ApplyMockIODiscardOutErr(cmd)
 
 	cmd.SetArgs([]string{
 		fmt.Sprintf("--%s=%s", flags.FlagHome, kbHome),

client/keys/mnemonic_test.go

@@ -2,7 +2,6 @@ package keys
 
 import (
 	"fmt"
-	"io/ioutil"
 	"strings"
 	"testing"
 
@@ -13,24 +12,22 @@ import (
 
 func Test_RunMnemonicCmdNormal(t *testing.T) {
 	cmd := MnemonicKeyCommand()
-	cmd.SetErr(ioutil.Discard)
-	cmd.SetOut(ioutil.Discard)
+	_ = testutil.ApplyMockIODiscardOutErr(cmd)
 	cmd.SetArgs([]string{})
 	require.NoError(t, cmd.Execute())
 }
 
 func Test_RunMnemonicCmdUser(t *testing.T) {
 	cmd := MnemonicKeyCommand()
-	cmd.SetErr(ioutil.Discard)
-	cmd.SetOut(ioutil.Discard)
+	_ = testutil.ApplyMockIODiscardOutErr(cmd)
 
 	cmd.SetArgs([]string{fmt.Sprintf("--%s=1", flagUserEntropy)})
 	err := cmd.Execute()
 	require.Error(t, err)
 	require.Equal(t, "EOF", err.Error())
 
 	// Try again
-	mockIn, _, _ := testutil.ApplyMockIO(cmd)
+	mockIn := testutil.ApplyMockIODiscardOutErr(cmd)
 	mockIn.Reset("Hi!\n")
 	err = cmd.Execute()
 	require.Error(t, err)

client/keys/show_test.go

@@ -38,7 +38,7 @@ func Test_showKeysCmd(t *testing.T) {
 func Test_runShowCmd(t *testing.T) {
 	cmd := ShowKeysCmd()
 	cmd.Flags().AddFlagSet(Commands().PersistentFlags())
-	mockIn, _, _ := testutil.ApplyMockIO(cmd)
+	mockIn := testutil.ApplyMockIODiscardOutErr(cmd)
 
 	cmd.SetArgs([]string{"invalid"})
 	require.EqualError(t, cmd.Execute(), "invalid is not a valid name or address: decoding bech32 failed: invalid bech32 string length 7")

testutil/ioutil.go

@@ -2,6 +2,7 @@ package testutil
 
 import (
 	"bytes"
+	"io"
 	"io/ioutil"
 	"os"
 	"strings"
@@ -20,15 +21,42 @@ func NewTestCaseDir(t testing.TB) (string, func()) {
 	return dir, func() { os.RemoveAll(dir) }
 }
 
+// BufferReader is implemented by types that read from a string buffer.
+type BufferReader interface {
+	io.Reader
+	Reset(string)
+}
+
+// BufferWriter is implemented by types that write to a buffer.
+type BufferWriter interface {
+	io.Writer
+	Reset()
+	String() string
+}
+
 // ApplyMockIO replaces stdin/out/err with buffers that can be used during testing.
-func ApplyMockIO(c *cobra.Command) (*strings.Reader, *bytes.Buffer, *bytes.Buffer) {
+// Returns an input BufferReader and an output BufferWriter.
+func ApplyMockIO(c *cobra.Command) (BufferReader, BufferWriter) {
 	mockIn := strings.NewReader("")
 	mockOut := bytes.NewBufferString("")
-	mockErr := bytes.NewBufferString("")
+
 	c.SetIn(mockIn)
 	c.SetOut(mockOut)
-	c.SetErr(mockErr)
-	return mockIn, mockOut, mockErr
+	c.SetErr(mockOut)
+
+	return mockIn, mockOut
+}
+
+// ApplyMockIODiscardOutputs replaces a cobra.Command output and error streams with a dummy io.Writer.
+// Replaces and returns the io.Reader associated to the cobra.Command input stream.
+func ApplyMockIODiscardOutErr(c *cobra.Command) BufferReader {
+	mockIn := strings.NewReader("")
+
+	c.SetIn(mockIn)
+	c.SetOut(ioutil.Discard)
+	c.SetErr(ioutil.Discard)
+
+	return mockIn
 }
 
 // Write the given string to a new temporary file.

testutil/ioutil_test.go

@@ -29,7 +29,6 @@ func TestNewTestCaseDir(t *testing.T) {
 
 func TestApplyMockIO(t *testing.T) {
 	cmd := &cobra.Command{}
-
 	oldStdin := cmd.InOrStdin()
 	oldStdout := cmd.OutOrStdout()
 	oldStderr := cmd.ErrOrStderr()
@@ -39,6 +38,7 @@ func TestApplyMockIO(t *testing.T) {
 	require.NotEqual(t, cmd.InOrStdin(), oldStdin)
 	require.NotEqual(t, cmd.OutOrStdout(), oldStdout)
 	require.NotEqual(t, cmd.ErrOrStderr(), oldStderr)
+	require.Equal(t, cmd.ErrOrStderr(), cmd.OutOrStdout())
 }
 
 func TestWriteToNewTempFile(t *testing.T) {
@@ -53,3 +53,13 @@ func TestWriteToNewTempFile(t *testing.T) {
 
 	require.NoFileExists(t, tempfile.Name())
 }
+
+func TestApplyMockIODiscardOutErr(t *testing.T) {
+	cmd := &cobra.Command{}
+	oldStdin := cmd.InOrStdin()
+
+	testutil.ApplyMockIODiscardOutErr(cmd)
+	require.NotEqual(t, cmd.InOrStdin(), oldStdin)
+	require.Equal(t, cmd.OutOrStdout(), ioutil.Discard)
+	require.Equal(t, cmd.ErrOrStderr(), ioutil.Discard)
+}

version/version_test.go

@@ -40,7 +40,7 @@ go version go1.14 linux/amd64`
 
 func Test_runVersionCmd(t *testing.T) {
 	cmd := NewVersionCommand()
-	_, mockOut, _ := testutil.ApplyMockIO(cmd)
+	_, mockOut := testutil.ApplyMockIO(cmd)
 
 	cmd.SetArgs([]string{
 		fmt.Sprintf("--%s=''", cli.OutputFlag),

x/auth/client/cli/broadcast_test.go

@@ -19,8 +19,7 @@ func TestGetBroadcastCommand_OfflineFlag(t *testing.T) {
 	clientCtx = clientCtx.WithTxGenerator(simappparams.MakeEncodingConfig().TxGenerator)
 
 	cmd := GetBroadcastCommand(clientCtx)
-	cmd.SetOut(ioutil.Discard)
-	cmd.SetErr(ioutil.Discard)
+	_ = testutil.ApplyMockIODiscardOutErr(cmd)
 	cmd.SetArgs([]string{fmt.Sprintf("--%s=true", flags.FlagOffline), ""})
 
 	require.EqualError(t, cmd.Execute(), "cannot broadcast tx during offline mode")

x/auth/client/cli/encode_test.go

@@ -2,7 +2,6 @@ package cli
 
 import (
 	"encoding/base64"
-	"io/ioutil"
 	"testing"
 
 	"github.com/stretchr/testify/require"
@@ -21,8 +20,7 @@ func TestGetCommandEncode(t *testing.T) {
 		WithJSONMarshaler(encodingConfig.Marshaler)
 
 	cmd := GetEncodeCommand(clientCtx)
-	cmd.SetErr(ioutil.Discard)
-	cmd.SetOut(ioutil.Discard)
+	_ = testutil.ApplyMockIODiscardOutErr(cmd)
 
 	authtypes.RegisterCodec(encodingConfig.Amino)
 	sdk.RegisterCodec(encodingConfig.Amino)
@@ -51,8 +49,7 @@ func TestGetCommandDecode(t *testing.T) {
 		WithJSONMarshaler(encodingConfig.Marshaler)
 
 	cmd := GetDecodeCommand(clientCtx)
-	cmd.SetErr(ioutil.Discard)
-	cmd.SetOut(ioutil.Discard)
+	_ = testutil.ApplyMockIODiscardOutErr(cmd)
 
 	sdk.RegisterCodec(encodingConfig.Amino)
 

x/genutil/client/cli/migrate_test.go

@@ -28,8 +28,7 @@ func TestMigrateGenesis(t *testing.T) {
 	target := "v0.36"
 
 	cmd := MigrateGenesisCmd()
-	cmd.SetErr(ioutil.Discard)
-	cmd.SetOut(ioutil.Discard)
+	_ = testutil.ApplyMockIODiscardOutErr(cmd)
 
 	clientCtx := client.Context{}.WithJSONMarshaler(cdc)
 	ctx := context.Background()