go.chromium.org/luci@v0.0.0-20240309015107-7cdc2e660f33/common/data/rand/cryptorand/cryptorand_test.go (about)

     1  // Copyright 2016 The LUCI Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //      http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package cryptorand
    16  
    17  import (
    18  	"context"
    19  	"testing"
    20  
    21  	. "github.com/smartystreets/goconvey/convey"
    22  )
    23  
    24  func TestCryptoRand(t *testing.T) {
    25  	t.Parallel()
    26  
    27  	Convey("test unmocked real rand", t, func() {
    28  		// Read bytes from real rand, make sure we don't crash.
    29  		n, err := Read(context.Background(), make([]byte, 16))
    30  		So(n, ShouldEqual, 16)
    31  		So(err, ShouldBeNil)
    32  	})
    33  
    34  	Convey("test mocked rand", t, func() {
    35  		ctx := MockForTest(context.Background(), 0)
    36  		buf := make([]byte, 16)
    37  		n, err := Read(ctx, buf)
    38  		So(n, ShouldEqual, 16)
    39  		So(err, ShouldBeNil)
    40  		So(buf, ShouldResemble, []byte{0xfa, 0x12, 0xf9, 0x2a, 0xfb, 0xe0, 0xf,
    41  			0x85, 0x8, 0xd0, 0xe8, 0x3b, 0xab, 0x9c, 0xf8, 0xce})
    42  	})
    43  }