test signal errors (#28)

* test signal errors

* fix documentation

signal.go

@@ -8,6 +8,7 @@ import (
 	"runtime"
 	"sync"
 	"sync/atomic"
+	"syscall"
 	"time"
 )
 
@@ -135,3 +136,32 @@ func (s *signalCtx) cancel(err error) {
 		close(s.done)
 	})
 }
+
+// IsSignal returns true if the given error is a *SignalError that was
+// generated upon receipt of one of the given signals. If no signal is
+// passed, the function only tests for err to be of type *SginalError.
+func IsSignal(err error, signals ...os.Signal) bool {
+	if e, ok := err.(*SignalError); ok {
+		if len(signals) == 0 {
+			return true
+		}
+		for _, signal := range signals {
+			if signal == e.Signal {
+				return true
+			}
+		}
+	}
+	return false
+}
+
+// IsTermination returns true if the given error was caused by receiving a
+// termination signal.
+func IsTermination(err error) bool {
+	return IsSignal(err, syscall.SIGTERM)
+}
+
+// IsInterruption returns true if the given error was caused by receiving an
+// interruption signal.
+func IsInterruption(err error) bool {
+	return IsSignal(err, syscall.SIGINT)
+}

signal_test.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"os"
 	"reflect"
+	"syscall"
 	"testing"
 	"time"
 )
@@ -117,3 +118,21 @@ func TestWithSignals(t *testing.T) {
 		}
 	})
 }
+
+func TestIsTermination(t *testing.T) {
+	if !IsTermination(&SignalError{Signal: syscall.SIGTERM}) {
+		t.Error("SIGTERM wasn't recognized as a termination error")
+	}
+	if IsTermination(&SignalError{Signal: syscall.SIGINT}) {
+		t.Error("SIGINT was mistakenly recognized as a termination error")
+	}
+}
+
+func TestIsInterruption(t *testing.T) {
+	if !IsInterruption(&SignalError{Signal: syscall.SIGINT}) {
+		t.Error("SIGINT wasn't recognized as a interruption error")
+	}
+	if IsInterruption(&SignalError{Signal: syscall.SIGTERM}) {
+		t.Error("SIGTERM was mistakenly recognized as a interruption error")
+	}
+}