mirror of https://github.com/knative/client.git
78 lines
2.2 KiB
Go
78 lines
2.2 KiB
Go
// Copyright 2020 The Knative Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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// http://www.apache.org/licenses/LICENSE-2.0
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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// OutputCapture allows to capture any text written to standard out or standard error
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// which is especially useful during testing.
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//
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// Call it like:
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//
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// capture := CaptureOutput(t)
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// doSomeActionThatWritesToStdOutAndStdErr()
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// stdOut, stdErr := capture.Close()
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//
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// CaptureOutput() and capture.Close() should always come in pairs as Close() also
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// restores the old streams
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package test
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import (
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"io/ioutil"
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"os"
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"testing"
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"gotest.tools/assert"
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)
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type OutputCapture struct {
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outRead, outWrite *os.File
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errorRead, errorWrite *os.File
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t *testing.T
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oldStdout *os.File
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oldStderr *os.File
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}
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// CaptureOutput sets up standard our and standard error to capture any
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// output which
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func CaptureOutput(t *testing.T) OutputCapture {
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ret := OutputCapture{
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oldStdout: os.Stdout,
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oldStderr: os.Stderr,
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t: t,
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}
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var err error
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ret.outRead, ret.outWrite, err = os.Pipe()
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assert.NilError(t, err)
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os.Stdout = ret.outWrite
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ret.errorRead, ret.errorWrite, err = os.Pipe()
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assert.NilError(t, err)
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os.Stderr = ret.errorWrite
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return ret
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}
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// Close return the output collected and restores the original standard out and error streams
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// (i.e. those that were present before the call to CaptureOutput).
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func (c OutputCapture) Close() (string, string) {
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err := c.outWrite.Close()
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assert.NilError(c.t, err)
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err = c.errorWrite.Close()
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assert.NilError(c.t, err)
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outOutput, err := ioutil.ReadAll(c.outRead)
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assert.NilError(c.t, err)
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errOutput, err := ioutil.ReadAll(c.errorRead)
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assert.NilError(c.t, err)
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os.Stdout = c.oldStdout
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os.Stderr = c.oldStderr
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return string(outOutput), string(errOutput)
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}
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