testr.go

Documentation: github.com/go-logr/logr/testr

     1  /*
     2  Copyright 2019 The logr Authors.
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8      http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  // Package testr provides support for using logr in tests.
    18  package testr
    19  
    20  import (
    21  	"testing"
    22  
    23  	"github.com/go-logr/logr"
    24  	"github.com/go-logr/logr/funcr"
    25  )
    26  
    27  // New returns a logr.Logger that prints through a testing.T object.
    28  // Info logs are only enabled at V(0).
    29  func New(t *testing.T) logr.Logger {
    30  	return NewWithOptions(t, Options{})
    31  }
    32  
    33  // Options carries parameters which influence the way logs are generated.
    34  type Options struct {
    35  	// LogTimestamp tells the logger to add a "ts" key to log
    36  	// lines. This has some overhead, so some users might not want
    37  	// it.
    38  	LogTimestamp bool
    39  
    40  	// Verbosity tells the logger which V logs to be write.
    41  	// Higher values enable more logs.
    42  	Verbosity int
    43  }
    44  
    45  // NewWithOptions returns a logr.Logger that prints through a testing.T object.
    46  // In contrast to the simpler New, output formatting can be configured.
    47  func NewWithOptions(t *testing.T, opts Options) logr.Logger {
    48  	l := &testlogger{
    49  		testloggerInterface: newLoggerInterfaceWithOptions(t, opts),
    50  	}
    51  	return logr.New(l)
    52  }
    53  
    54  // TestingT is an interface wrapper around testing.T, testing.B and testing.F.
    55  type TestingT interface {
    56  	Helper()
    57  	Log(args ...any)
    58  }
    59  
    60  // NewWithInterface returns a logr.Logger that prints through a
    61  // TestingT object.
    62  // In contrast to the simpler New, output formatting can be configured.
    63  func NewWithInterface(t TestingT, opts Options) logr.Logger {
    64  	l := newLoggerInterfaceWithOptions(t, opts)
    65  	return logr.New(&l)
    66  }
    67  
    68  func newLoggerInterfaceWithOptions(t TestingT, opts Options) testloggerInterface {
    69  	return testloggerInterface{
    70  		t: t,
    71  		Formatter: funcr.NewFormatter(funcr.Options{
    72  			LogTimestamp: opts.LogTimestamp,
    73  			Verbosity:    opts.Verbosity,
    74  		}),
    75  	}
    76  }
    77  
    78  // Underlier exposes access to the underlying testing.T instance. Since
    79  // callers only have a logr.Logger, they have to know which
    80  // implementation is in use, so this interface is less of an
    81  // abstraction and more of a way to test type conversion.
    82  type Underlier interface {
    83  	GetUnderlying() *testing.T
    84  }
    85  
    86  // UnderlierInterface exposes access to the underlying TestingT instance. Since
    87  // callers only have a logr.Logger, they have to know which
    88  // implementation is in use, so this interface is less of an
    89  // abstraction and more of a way to test type conversion.
    90  type UnderlierInterface interface {
    91  	GetUnderlying() TestingT
    92  }
    93  
    94  // Info logging implementation shared between testLogger and testLoggerInterface.
    95  func logInfo(t TestingT, formatInfo func(int, string, []any) (string, string), level int, msg string, kvList ...any) {
    96  	prefix, args := formatInfo(level, msg, kvList)
    97  	t.Helper()
    98  	if prefix != "" {
    99  		args = prefix + ": " + args
   100  	}
   101  	t.Log(args)
   102  }
   103  
   104  // Error logging implementation shared between testLogger and testLoggerInterface.
   105  func logError(t TestingT, formatError func(error, string, []any) (string, string), err error, msg string, kvList ...any) {
   106  	prefix, args := formatError(err, msg, kvList)
   107  	t.Helper()
   108  	if prefix != "" {
   109  		args = prefix + ": " + args
   110  	}
   111  	t.Log(args)
   112  }
   113  
   114  // This type exists to wrap and modify the method-set of testloggerInterface.
   115  // In particular, it changes the GetUnderlying() method.
   116  type testlogger struct {
   117  	testloggerInterface
   118  }
   119  
   120  func (l testlogger) GetUnderlying() *testing.T {
   121  	// This method is defined on testlogger, so the only type this could
   122  	// possibly be is testing.T, even though that's not guaranteed by the type
   123  	// system itself.
   124  	return l.t.(*testing.T) //nolint:forcetypeassert
   125  }
   126  
   127  type testloggerInterface struct {
   128  	funcr.Formatter
   129  	t TestingT
   130  }
   131  
   132  func (l testloggerInterface) WithName(name string) logr.LogSink {
   133  	l.Formatter.AddName(name)
   134  	return &l
   135  }
   136  
   137  func (l testloggerInterface) WithValues(kvList ...any) logr.LogSink {
   138  	l.Formatter.AddValues(kvList)
   139  	return &l
   140  }
   141  
   142  func (l testloggerInterface) GetCallStackHelper() func() {
   143  	return l.t.Helper
   144  }
   145  
   146  func (l testloggerInterface) Info(level int, msg string, kvList ...any) {
   147  	l.t.Helper()
   148  	logInfo(l.t, l.FormatInfo, level, msg, kvList...)
   149  }
   150  
   151  func (l testloggerInterface) Error(err error, msg string, kvList ...any) {
   152  	l.t.Helper()
   153  	logError(l.t, l.FormatError, err, msg, kvList...)
   154  }
   155  
   156  func (l testloggerInterface) GetUnderlying() TestingT {
   157  	return l.t
   158  }
   159  
   160  // Assert conformance to the interfaces.
   161  var _ logr.LogSink = &testlogger{}
   162  var _ logr.CallStackHelperLogSink = &testlogger{}
   163  var _ Underlier = &testlogger{}
   164  
   165  var _ logr.LogSink = &testloggerInterface{}
   166  var _ logr.CallStackHelperLogSink = &testloggerInterface{}
   167  var _ UnderlierInterface = &testloggerInterface{}
   168
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