github.com/cosmos/cosmos-sdk@v0.50.10/testutil/ioutil.go (about)

     1  package testutil
     2  
     3  import (
     4  	"bytes"
     5  	"io"
     6  	"os"
     7  	"strings"
     8  	"testing"
     9  
    10  	"github.com/spf13/cobra"
    11  	"github.com/stretchr/testify/require"
    12  )
    13  
    14  // BufferReader is implemented by types that read from a string buffer.
    15  type BufferReader interface {
    16  	io.Reader
    17  	Reset(string)
    18  }
    19  
    20  // BufferWriter is implemented by types that write to a buffer.
    21  type BufferWriter interface {
    22  	io.Writer
    23  	Reset()
    24  	Bytes() []byte
    25  	String() string
    26  }
    27  
    28  // ApplyMockIO replaces stdin/out/err with buffers that can be used during testing.
    29  // Returns an input BufferReader and an output BufferWriter.
    30  func ApplyMockIO(c *cobra.Command) (BufferReader, BufferWriter) {
    31  	mockIn := strings.NewReader("")
    32  	mockOut := bytes.NewBufferString("")
    33  
    34  	c.SetIn(mockIn)
    35  	c.SetOut(mockOut)
    36  	c.SetErr(mockOut)
    37  
    38  	return mockIn, mockOut
    39  }
    40  
    41  // ApplyMockIODiscardOutputs replaces a cobra.Command output and error streams with a dummy io.Writer.
    42  // Replaces and returns the io.Reader associated to the cobra.Command input stream.
    43  func ApplyMockIODiscardOutErr(c *cobra.Command) BufferReader {
    44  	mockIn := strings.NewReader("")
    45  
    46  	c.SetIn(mockIn)
    47  	c.SetOut(io.Discard)
    48  	c.SetErr(io.Discard)
    49  
    50  	return mockIn
    51  }
    52  
    53  // Write the given string to a new temporary file.
    54  // Returns an open file for the test to use.
    55  func WriteToNewTempFile(t testing.TB, s string) *os.File {
    56  	t.Helper()
    57  
    58  	fp := TempFile(t)
    59  	_, err := fp.WriteString(s)
    60  
    61  	require.Nil(t, err)
    62  
    63  	return fp
    64  }
    65  
    66  // TempFile returns a writable temporary file for the test to use.
    67  func TempFile(t testing.TB) *os.File {
    68  	t.Helper()
    69  
    70  	fp, err := os.CreateTemp(GetTempDir(t), "")
    71  	require.NoError(t, err)
    72  
    73  	return fp
    74  }
    75  
    76  // GetTempDir returns a writable temporary director for the test to use.
    77  func GetTempDir(t testing.TB) string {
    78  	t.Helper()
    79  	// os.MkDir() is used instead of testing.T.TempDir()
    80  	// see https://github.com/cosmos/cosmos-sdk/pull/8475 and
    81  	// https://github.com/cosmos/cosmos-sdk/pull/10341 for
    82  	// this change's rationale.
    83  	tempdir, err := os.MkdirTemp("", "")
    84  	require.NoError(t, err)
    85  	t.Cleanup(func() { _ = os.RemoveAll(tempdir) })
    86  	return tempdir
    87  }