github.com/amplia-iiot/yutil@v1.0.1-0.20231229120411-5d96a4c5a136/internal/testing/stdin.go (about)

     1  /*
     2  Copyright (c) 2021 amplia-iiot
     3  
     4  Permission is hereby granted, free of charge, to any person obtaining a copy
     5  of this software and associated documentation files (the "Software"), to deal
     6  in the Software without restriction, including without limitation the rights
     7  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
     8  copies of the Software, and to permit persons to whom the Software is
     9  furnished to do so, subject to the following conditions:
    10  
    11  The above copyright notice and this permission notice shall be included in all
    12  copies or substantial portions of the Software.
    13  
    14  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    15  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    16  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    17  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    18  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    19  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
    20  SOFTWARE.
    21  */
    22  
    23  package testing
    24  
    25  import (
    26  	"os"
    27  	"testing"
    28  )
    29  
    30  // SimulateStdinContent executes a function that reads stdin simulating the
    31  // content. Fails on error.
    32  func SimulateStdinContent(t *testing.T, stdin string, function func()) {
    33  	// Create temporal file
    34  	tmp, err := os.CreateTemp("tmp", "stdin-*.yml")
    35  	if err != nil {
    36  		t.Fatal(err)
    37  	}
    38  	// Clean up on exit
    39  	defer os.Remove(tmp.Name())
    40  
    41  	// Write custom content
    42  	if _, err := tmp.Write([]byte(stdin)); err != nil {
    43  		t.Fatal(err)
    44  	}
    45  
    46  	// Reset offset for next read
    47  	if _, err := tmp.Seek(0, 0); err != nil {
    48  		t.Fatal(err)
    49  	}
    50  
    51  	SimulateStdinFile(*tmp, function)
    52  }
    53  
    54  // SimulateStdinFile executes a function that reads stdin using another file as
    55  // simulated stdin. Fails on error.
    56  func SimulateStdinFile(stdin os.File, function func()) {
    57  	originalStdin := os.Stdin
    58  	defer func() { os.Stdin = originalStdin }()
    59  
    60  	os.Stdin = &stdin
    61  
    62  	// Execute function that uses stdin
    63  	function()
    64  }