Add tests for invalid reflect values.

spew/internal_test.go

@@ -0,0 +1,79 @@
+/*
+ * Copyright (c) 2013 Dave Collins <dave@davec.name>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+/*
+This test file is part of the spew package rather than than the spew_test
+package because it needs access to internals to properly test certain cases
+which are not possible via the public interface since they should never happen.
+*/
+
+package spew
+
+import (
+	"bytes"
+	"reflect"
+	"testing"
+)
+
+// dummyFmtState implements a fake fmt.State to use for testing invalid
+// reflect.Value handling.  This is necessary because the fmt package catches
+// invalid values before invoking the formatter on them.
+type dummyFmtState struct {
+	bytes.Buffer
+}
+
+func (dfs *dummyFmtState) Flag(f int) bool {
+	return false
+}
+
+func (dfs *dummyFmtState) Precision() (int, bool) {
+	return 0, false
+}
+
+func (dfs *dummyFmtState) Width() (int, bool) {
+	return 0, false
+}
+
+// TestDumpInvalidReflectValue ensures the dump code handles an invalid reflect
+// value properly.  This needs access to internal state since it should never
+// happen in real code and therefore can't be tested via the public API.
+func TestDumpInvalidReflectValue(t *testing.T) {
+	v := new(reflect.Value)
+	buf := new(bytes.Buffer)
+	d := dumpState{w: buf, cs: &Config}
+	d.dump(*v)
+	s := buf.String()
+	want := "<invalid>"
+	if s != want {
+		t.Errorf("DumpInvalidReflectValue\n got: %s want: %s", s, want)
+	}
+}
+
+// TestFormatterInvalidReflectValue ensures the formatter code handles an
+// invalid reflect value properly.  This needs access to internal state since it
+// should never happen in real code and therefore can't be tested via the public
+// API.
+func TestFormatterInvalidReflectValue(t *testing.T) {
+	v := new(reflect.Value)
+	buf := new(dummyFmtState)
+	f := formatState{value: *v, cs: &Config, fs: buf}
+	f.format(*v)
+	s := buf.String()
+	want := "<invalid>"
+	if s != want {
+		t.Errorf("FormatterInvalidReflectValue\n got: %s want: %s", s, want)
+	}
+}