- fix nil test so that []interface{} when nil works correctly

- use switch for haslength.go

has/haslength.go

@@ -19,10 +19,11 @@ func Length(expected interface{}) *gocrest.Matcher {
 		}
 		lenOfActual := reflect.ValueOf(actual).Len()
 		matcher.Actual = fmt.Sprintf("length was %d", lenOfActual)
-		typeMatcher, ok := expected.(*gocrest.Matcher)
-		if ok {
-			matcher.Describe = fmt.Sprintf(description, typeMatcher.Describe)
-			return typeMatcher.Matches(lenOfActual)
+		switch expected.(type) {
+		case *gocrest.Matcher:
+			m := expected.(*gocrest.Matcher)
+			matcher.Describe = fmt.Sprintf(description, m.Describe)
+			return m.Matches(lenOfActual)
 		}
 		return lenOfActual == expected
 	}

is/nil.go

@@ -1,8 +1,25 @@
 package is
 
-import "github.com/corbym/gocrest"
+import (
+	"fmt"
+	"github.com/corbym/gocrest"
+	"reflect"
+)
 
-//Nil matches if the expected value is nil
+//Nil matches if the actual value is nil
 func Nil() *gocrest.Matcher {
-	return EqualTo(nil)
+	match := new(gocrest.Matcher)
+	match.Describe = "value that is <nil>"
+	match.Matches = func(actual interface{}) bool {
+		match.Actual = fmt.Sprintf("%v", actual)
+		if actual == nil {
+			return true
+		}
+		switch reflect.TypeOf(actual).Kind() {
+		case reflect.Ptr, reflect.Map, reflect.Array, reflect.Chan, reflect.Slice:
+			return reflect.ValueOf(actual).IsNil()
+		}
+		return false // anything else is never nil (hopefully)
+	}
+	return match
 }

matcher_test.go

@@ -556,7 +556,7 @@ func TestMatcherDescription(t *testing.T) {
 		{description: "GreaterThanOrEqual", actual: 1, matcher: is.GreaterThanOrEqualTo(2), expected: "any of (value greater than <2> or value equal to <2>)"},
 		{description: "LessThan", actual: 2, matcher: is.LessThan(1), expected: "value less than <1>"},
 		{description: "LessThanOrEqualTo", actual: 2, matcher: is.LessThanOrEqualTo(1), expected: "any of (value less than <1> or value equal to <1>)"},
-		{description: "Nil", actual: 1, matcher: is.Nil(), expected: "value equal to <<nil>>"},
+		{description: "Nil", actual: 1, matcher: is.Nil(), expected: "value that is <nil>"},
 		{description: "ValueContaining", actual: []string{"Foo", "Bar"}, matcher: is.ValueContaining([]string{"Baz", "Bing"}), expected: "something that contains [Baz Bing]"},
 		{description: "ValueContaining", actual: []string{"Foo", "Bar"}, matcher: is.ValueContaining(is.EqualTo("Baz"), is.EqualTo("Bing")), expected: "something that contains value equal to <Baz> and value equal to <Bing>"},
 		{description: "MatchesPattern", actual: "blarney stone", matcher: is.MatchForPattern("~123.?.*"), expected: "a value that matches pattern ~123.?.*"},
@@ -663,6 +663,16 @@ func TestTypeName(t *testing.T) {
 	}
 }
 
+func TestNilArrayInterface(t *testing.T) {
+	actual := nilResponse()
+
+	then.AssertThat(t, actual, is.Nil())
+}
+
+func nilResponse() []interface{} {
+	return nil
+}
+
 func TestEveryElement(t *testing.T) {
 	tests := []struct {
 		actual     interface{}