Moving mlog to corelibs (#16915)

* Moving mlog to corelibs

* Regenerating app layers

* Fix golangci-lint problem

* Fixing golangci-lint errors

* Renaming from corelibs to shared

* Renaming from corelibs to shared

* Fixing import

* Fixing merge problems

* Fixing build

shared/mlog/stdlog_test.go

@@ -0,0 +1,42 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package mlog
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"go.uber.org/zap/zapcore"
+)
+
+func TestStdLogInterpretZapEntry(t *testing.T) {
+	for _, tc := range []struct {
+		testname        string
+		message         string
+		expectedMessage string
+		expectedLevel   zapcore.Level
+	}{
+		{"Debug Basic", "[DEBUG]My message", "My message", zapcore.DebugLevel},
+		{"Debug Basic2", "[DEBG]My message", "My message", zapcore.DebugLevel},
+		{"Warn Basic", "[WARN]My message", "My message", zapcore.WarnLevel},
+		{"Error Basic", "[ERROR]My message", "My message", zapcore.ErrorLevel},
+		{"Error Basic2", "[EROR]My message", "My message", zapcore.ErrorLevel},
+		{"Error Basic3", "[ERR]My message", "My message", zapcore.ErrorLevel},
+		{"Info Basic", "[INFO]My message", "My message", zapcore.InfoLevel},
+		{"Unknown level", "[UNKNOWN]My message", "[UNKNOWN]My message", zapcore.PanicLevel},
+		{"No level", "My message", "My message", zapcore.PanicLevel},
+		{"Empty message", "", "", zapcore.PanicLevel},
+		{"Malformed level", "INFO]My message", "INFO]My message", zapcore.PanicLevel},
+	} {
+		t.Run(tc.testname, func(t *testing.T) {
+			inEntry := zapcore.Entry{
+				Level:   zapcore.PanicLevel,
+				Message: tc.message,
+			}
+			resultEntry := stdLogInterpretZapEntry(inEntry)
+			assert.Equal(t, tc.expectedMessage, resultEntry.Message)
+			assert.Equal(t, tc.expectedLevel, resultEntry.Level)
+		})
+	}
+}