@@ -12,6 +12,9 @@ type causal interface {

 }

 func TestNotFound(t *testing.T) {

+	if IsNotFound(errTest) {

+		t.Fatalf("did not expect not found error, got %T", errTest)

+	}

 	e := NotFound(errTest)

 	if !IsNotFound(e) {

 		t.Fatalf("expected not found error, got: %T", e)

@@ -22,6 +25,9 @@ func TestNotFound(t *testing.T) {

 }

 func TestConflict(t *testing.T) {

+	if IsConflict(errTest) {

+		t.Fatalf("did not expect conflcit error, got %T", errTest)

+	}

 	e := Conflict(errTest)

 	if !IsConflict(e) {

 		t.Fatalf("expected conflcit error, got: %T", e)

@@ -32,6 +38,9 @@ func TestConflict(t *testing.T) {

 }

 func TestForbidden(t *testing.T) {

+	if IsForbidden(errTest) {

+		t.Fatalf("did not expect forbidden error, got %T", errTest)

+	}

 	e := Forbidden(errTest)

 	if !IsForbidden(e) {

 		t.Fatalf("expected forbidden error, got: %T", e)

@@ -42,6 +51,9 @@ func TestForbidden(t *testing.T) {

 }

 func TestInvalidParameter(t *testing.T) {

+	if IsInvalidParameter(errTest) {

+		t.Fatalf("did not expect invalid argument error, got %T", errTest)

+	}

 	e := InvalidParameter(errTest)

 	if !IsInvalidParameter(e) {

 		t.Fatalf("expected invalid argument error, got %T", e)

@@ -52,6 +64,9 @@ func TestInvalidParameter(t *testing.T) {

 }

 func TestNotImplemented(t *testing.T) {

+	if IsNotImplemented(errTest) {

+		t.Fatalf("did not expect not implemented error, got %T", errTest)

+	}

 	e := NotImplemented(errTest)

 	if !IsNotImplemented(e) {

 		t.Fatalf("expected not implemented error, got %T", e)

@@ -62,6 +77,9 @@ func TestNotImplemented(t *testing.T) {

 }

 func TestNotModified(t *testing.T) {

+	if IsNotModified(errTest) {

+		t.Fatalf("did not expect not modified error, got %T", errTest)

+	}

 	e := NotModified(errTest)

 	if !IsNotModified(e) {

 		t.Fatalf("expected not modified error, got %T", e)

@@ -72,6 +90,9 @@ func TestNotModified(t *testing.T) {

 }

 func TestAlreadyExists(t *testing.T) {

+	if IsAlreadyExists(errTest) {

+		t.Fatalf("did not expect already exists error, got %T", errTest)

+	}

 	e := AlreadyExists(errTest)

 	if !IsAlreadyExists(e) {

 		t.Fatalf("expected already exists error, got %T", e)

@@ -82,6 +103,9 @@ func TestAlreadyExists(t *testing.T) {

 }

 func TestUnauthorized(t *testing.T) {

+	if IsUnauthorized(errTest) {

+		t.Fatalf("did not expect unauthorized error, got %T", errTest)

+	}

 	e := Unauthorized(errTest)

 	if !IsUnauthorized(e) {

 		t.Fatalf("expected unauthorized error, got %T", e)

@@ -92,6 +116,9 @@ func TestUnauthorized(t *testing.T) {

 }

 func TestUnknown(t *testing.T) {

+	if IsUnknown(errTest) {

+		t.Fatalf("did not expect unknown error, got %T", errTest)

+	}

 	e := Unknown(errTest)

 	if !IsUnknown(e) {

 		t.Fatalf("expected unknown error, got %T", e)

@@ -102,9 +129,12 @@ func TestUnknown(t *testing.T) {

 }

 func TestCancelled(t *testing.T) {

+	if IsCancelled(errTest) {

+		t.Fatalf("did not expect cancelled error, got %T", errTest)

+	}

 	e := Cancelled(errTest)

 	if !IsCancelled(e) {

-		t.Fatalf("expected canclled error, got %T", e)

+		t.Fatalf("expected cancelled error, got %T", e)

 	}

 	if cause := e.(causal).Cause(); cause != errTest {

 		t.Fatalf("causual should be errTest, got: %v", cause)

@@ -112,6 +142,9 @@ func TestCancelled(t *testing.T) {

 }

 func TestDeadline(t *testing.T) {

+	if IsDeadline(errTest) {

+		t.Fatalf("did not expect deadline error, got %T", errTest)

+	}

 	e := Deadline(errTest)

 	if !IsDeadline(e) {

 		t.Fatalf("expected deadline error, got %T", e)

@@ -121,7 +154,10 @@ func TestDeadline(t *testing.T) {

 	}

 }

-func TestIsDataLoss(t *testing.T) {

+func TestDataLoss(t *testing.T) {

+	if IsDataLoss(errTest) {

+		t.Fatalf("did not expect data loss error, got %T", errTest)

+	}

 	e := DataLoss(errTest)

 	if !IsDataLoss(e) {

 		t.Fatalf("expected data loss error, got %T", e)

@@ -130,3 +166,16 @@ func TestIsDataLoss(t *testing.T) {

 		t.Fatalf("causual should be errTest, got: %v", cause)

 	}

 }

+

+func TestUnavailable(t *testing.T) {

+	if IsUnavailable(errTest) {

+		t.Fatalf("did not expect unavaillable error, got %T", errTest)

+	}

+	e := Unavailable(errTest)

+	if !IsUnavailable(e) {

+		t.Fatalf("expected unavaillable error, got %T", e)

+	}

+	if cause := e.(causal).Cause(); cause != errTest {

+		t.Fatalf("causual should be errTest, got: %v", cause)

+	}

+}

@@ -21,7 +21,7 @@ func getImplementer(err error) error {

 		ErrDeadline,

 		ErrDataLoss,

 		ErrUnknown:

-		return e

+		return err

 	case causer:

 		return getImplementer(e.Cause())

 	default: