move implementation to internal/ directory (#828)

internal/logger/testlogger.go

@@ -0,0 +1,28 @@
+package logger
+
+import (
+	"testing"
+)
+
+type testLogger struct {
+	Logger
+}
+
+type testingLoggerOutlet struct {
+	t *testing.T
+}
+
+func (o testingLoggerOutlet) WriteEntry(entry Entry) error {
+	o.t.Logf("%#v", entry)
+	return nil
+}
+
+var _ Logger = testLogger{}
+
+func NewTestLogger(t *testing.T) Logger {
+	outlets := NewOutlets()
+	outlets.Add(&testingLoggerOutlet{t}, Debug)
+	return &testLogger{
+		Logger: NewLogger(outlets, 0),
+	}
+}