internal/impl: add extensive tests for enum and messages

Add more extensive tests to ensure that the reflective API works for both
enums and messages. We tests the situation where a v2 message has dependencies
on v1 messages and vice versa.

Change-Id: Ib85d465711728ae13743bea700b678d9dda5e85c
Reviewed-on: https://go-review.googlesource.com/c/149758
Reviewed-by: Herbie Ong <herbie@google.com>
diff --git a/internal/impl/message_test.go b/internal/impl/message_test.go
index 69b5764..5852896 100644
--- a/internal/impl/message_test.go
+++ b/internal/impl/message_test.go
@@ -10,91 +10,116 @@
 	"strings"
 	"testing"
 
-	"github.com/google/go-cmp/cmp"
-	"github.com/google/go-cmp/cmp/cmpopts"
-
 	protoV1 "github.com/golang/protobuf/proto"
 	descriptorV1 "github.com/golang/protobuf/protoc-gen-go/descriptor"
 	pref "github.com/golang/protobuf/v2/reflect/protoreflect"
 	ptype "github.com/golang/protobuf/v2/reflect/prototype"
-)
+	cmp "github.com/google/go-cmp/cmp"
+	cmpopts "github.com/google/go-cmp/cmp/cmpopts"
 
-func mustMakeMessageDesc(t ptype.StandaloneMessage) pref.MessageDescriptor {
-	md, err := ptype.NewMessage(&t)
-	if err != nil {
-		panic(err)
-	}
-	return md
-}
-
-var V = pref.ValueOf
-
-type (
-	MyBool    bool
-	MyInt32   int32
-	MyInt64   int64
-	MyUint32  uint32
-	MyUint64  uint64
-	MyFloat32 float32
-	MyFloat64 float64
-	MyString  string
-	MyBytes   []byte
-
-	ListStrings []MyString
-	ListBytes   []MyBytes
-
-	MapStrings map[MyString]MyString
-	MapBytes   map[MyString]MyBytes
+	proto2_20180125 "github.com/golang/protobuf/v2/internal/testprotos/legacy/proto2.v1.0.0-20180125-92554152"
+	pvalue "github.com/golang/protobuf/v2/internal/value"
 )
 
 // List of test operations to perform on messages, lists, or maps.
 type (
-	messageOp  interface{} // equalMessage | hasFields | getFields | setFields | clearFields | listFields | mapFields
+	messageOp  interface{ isMessageOp() }
 	messageOps []messageOp
 
-	listOp  interface{} // equalList | lenList | getList | setList | appendList | truncList
+	listOp  interface{ isListOp() }
 	listOps []listOp
 
-	mapOp  interface{} // equalMap | lenMap | hasMap | getMap | setMap | clearMap | rangeMap
+	mapOp  interface{ isMapOp() }
 	mapOps []mapOp
 )
 
 // Test operations performed on a message.
 type (
-	equalMessage  pref.Message
-	hasFields     map[pref.FieldNumber]bool
-	getFields     map[pref.FieldNumber]pref.Value
-	setFields     map[pref.FieldNumber]pref.Value
-	clearFields   map[pref.FieldNumber]bool
-	listFields    map[pref.FieldNumber]listOps
-	mapFields     map[pref.FieldNumber]mapOps
+	// check that the message contents match
+	equalMessage struct{ pref.Message }
+	// check presence for specific fields in the message
+	hasFields map[pref.FieldNumber]bool
+	// check that specific message fields match
+	getFields map[pref.FieldNumber]pref.Value
+	// set specific message fields
+	setFields map[pref.FieldNumber]pref.Value
+	// clear specific fields in the message
+	clearFields []pref.FieldNumber
+	// apply messageOps on each specified message field
 	messageFields map[pref.FieldNumber]messageOps
-	// TODO: Mutable, Range, ExtensionTypes
+	// apply listOps on each specified list field
+	listFields map[pref.FieldNumber]listOps
+	// apply mapOps on each specified map fields
+	mapFields map[pref.FieldNumber]mapOps
+	// range through all fields and check that they match
+	rangeFields map[pref.FieldNumber]pref.Value
 )
 
+func (equalMessage) isMessageOp()  {}
+func (hasFields) isMessageOp()     {}
+func (getFields) isMessageOp()     {}
+func (setFields) isMessageOp()     {}
+func (clearFields) isMessageOp()   {}
+func (messageFields) isMessageOp() {}
+func (listFields) isMessageOp()    {}
+func (mapFields) isMessageOp()     {}
+func (rangeFields) isMessageOp()   {}
+
 // Test operations performed on a list.
 type (
-	equalList  pref.List
-	lenList    int
-	getList    map[int]pref.Value
-	setList    map[int]pref.Value
+	// check that the list contents match
+	equalList struct{ pref.List }
+	// check that list length matches
+	lenList int
+	// check that specific list entries match
+	getList map[int]pref.Value
+	// set specific list entries
+	setList map[int]pref.Value
+	// append entries to the list
 	appendList []pref.Value
-	truncList  int
-	// TODO: Mutable, MutableAppend
+	// apply messageOps on a newly appended message
+	appendMessageList messageOps
+	// truncate the list to the specified length
+	truncList int
 )
 
+func (equalList) isListOp()         {}
+func (lenList) isListOp()           {}
+func (getList) isListOp()           {}
+func (setList) isListOp()           {}
+func (appendList) isListOp()        {}
+func (appendMessageList) isListOp() {}
+func (truncList) isListOp()         {}
+
 // Test operations performed on a map.
 type (
-	equalMap pref.Map
-	lenMap   int
-	hasMap   map[interface{}]bool
-	getMap   map[interface{}]pref.Value
-	setMap   map[interface{}]pref.Value
-	clearMap map[interface{}]bool
+	// check that the map contents match
+	equalMap struct{ pref.Map }
+	// check that map length matches
+	lenMap int
+	// check presence for specific entries in the map
+	hasMap map[interface{}]bool
+	// check that specific map entries match
+	getMap map[interface{}]pref.Value
+	// set specific map entries
+	setMap map[interface{}]pref.Value
+	// clear specific entries in the map
+	clearMap []interface{}
+	// apply messageOps on each specified message entry
+	messageMap map[interface{}]messageOps
+	// range through all entries and check that they match
 	rangeMap map[interface{}]pref.Value
-	// TODO: Mutable
 )
 
+func (equalMap) isMapOp()   {}
+func (lenMap) isMapOp()     {}
+func (hasMap) isMapOp()     {}
+func (getMap) isMapOp()     {}
+func (setMap) isMapOp()     {}
+func (clearMap) isMapOp()   {}
+func (messageMap) isMapOp() {}
+func (rangeMap) isMapOp()   {}
+
 type ScalarProto2 struct {
 	Bool    *bool    `protobuf:"1"`
 	Int32   *int32   `protobuf:"2"`
@@ -121,6 +146,43 @@
 	MyBytesA  *MyString  `protobuf:"22"`
 }
 
+func mustMakeEnumDesc(t ptype.StandaloneEnum) pref.EnumDescriptor {
+	ed, err := ptype.NewEnum(&t)
+	if err != nil {
+		panic(err)
+	}
+	return ed
+}
+
+func mustMakeMessageDesc(t ptype.StandaloneMessage) pref.MessageDescriptor {
+	md, err := ptype.NewMessage(&t)
+	if err != nil {
+		panic(err)
+	}
+	return md
+}
+
+var V = pref.ValueOf
+var VE = func(n pref.EnumNumber) pref.Value { return V(n) }
+
+type (
+	MyBool    bool
+	MyInt32   int32
+	MyInt64   int64
+	MyUint32  uint32
+	MyUint64  uint64
+	MyFloat32 float32
+	MyFloat64 float64
+	MyString  string
+	MyBytes   []byte
+
+	ListStrings []MyString
+	ListBytes   []MyBytes
+
+	MapStrings map[MyString]MyString
+	MapBytes   map[MyString]MyBytes
+)
+
 var scalarProto2Type = MessageType{Type: ptype.GoMessage(
 	mustMakeMessageDesc(ptype.StandaloneMessage{
 		Syntax:   pref.Proto2,
@@ -181,15 +243,12 @@
 			1: true, 2: true, 3: true, 4: true, 5: true, 6: true, 7: true, 8: true, 9: true, 10: true, 11: true,
 			12: true, 13: true, 14: true, 15: true, 16: true, 17: true, 18: true, 19: true, 20: true, 21: true, 22: true,
 		},
-		equalMessage(&ScalarProto2{
+		equalMessage{&ScalarProto2{
 			new(bool), new(int32), new(int64), new(uint32), new(uint64), new(float32), new(float64), new(string), []byte{}, []byte{}, new(string),
 			new(MyBool), new(MyInt32), new(MyInt64), new(MyUint32), new(MyUint64), new(MyFloat32), new(MyFloat64), new(MyString), MyBytes{}, MyBytes{}, new(MyString),
-		}),
-		clearFields{
-			1: true, 2: true, 3: true, 4: true, 5: true, 6: true, 7: true, 8: true, 9: true, 10: true, 11: true,
-			12: true, 13: true, 14: true, 15: true, 16: true, 17: true, 18: true, 19: true, 20: true, 21: true, 22: true,
-		},
-		equalMessage(&ScalarProto2{}),
+		}},
+		clearFields{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22},
+		equalMessage{&ScalarProto2{}},
 	})
 }
 
@@ -279,7 +338,7 @@
 			1: false, 2: false, 3: false, 4: false, 5: false, 6: false, 7: false, 8: false, 9: false, 10: false, 11: false,
 			12: false, 13: false, 14: false, 15: false, 16: false, 17: false, 18: false, 19: false, 20: false, 21: false, 22: false,
 		},
-		equalMessage(&ScalarProto3{}),
+		equalMessage{&ScalarProto3{}},
 		setFields{
 			1: V(bool(true)), 2: V(int32(2)), 3: V(int64(3)), 4: V(uint32(4)), 5: V(uint64(5)), 6: V(float32(6)), 7: V(float64(7)), 8: V(string("8")), 9: V(string("9")), 10: V([]byte("10")), 11: V([]byte("11")),
 			12: V(bool(true)), 13: V(int32(13)), 14: V(int64(14)), 15: V(uint32(15)), 16: V(uint64(16)), 17: V(float32(17)), 18: V(float64(18)), 19: V(string("19")), 20: V(string("20")), 21: V([]byte("21")), 22: V([]byte("22")),
@@ -288,15 +347,12 @@
 			1: true, 2: true, 3: true, 4: true, 5: true, 6: true, 7: true, 8: true, 9: true, 10: true, 11: true,
 			12: true, 13: true, 14: true, 15: true, 16: true, 17: true, 18: true, 19: true, 20: true, 21: true, 22: true,
 		},
-		equalMessage(&ScalarProto3{
+		equalMessage{&ScalarProto3{
 			true, 2, 3, 4, 5, 6, 7, "8", []byte("9"), []byte("10"), "11",
 			true, 13, 14, 15, 16, 17, 18, "19", []byte("20"), []byte("21"), "22",
-		}),
-		clearFields{
-			1: true, 2: true, 3: true, 4: true, 5: true, 6: true, 7: true, 8: true, 9: true, 10: true, 11: true,
-			12: true, 13: true, 14: true, 15: true, 16: true, 17: true, 18: true, 19: true, 20: true, 21: true, 22: true,
-		},
-		equalMessage(&ScalarProto3{}),
+		}},
+		clearFields{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22},
+		equalMessage{&ScalarProto3{}},
 	})
 }
 
@@ -402,7 +458,7 @@
 				lenList(0),
 				appendList{V(int32(2)), V(int32(math.MinInt32)), V(int32(math.MaxInt32))},
 				getList{0: V(int32(2)), 1: V(int32(math.MinInt32)), 2: V(int32(math.MaxInt32))},
-				equalList(wantFS.Get(2).List()),
+				equalList{wantFS.Get(2).List()},
 			},
 			4: {
 				appendList{V(uint32(0)), V(uint32(0)), V(uint32(0))},
@@ -411,45 +467,45 @@
 			},
 			6: {
 				appendList{V(float32(6)), V(float32(math.SmallestNonzeroFloat32)), V(float32(math.NaN())), V(float32(math.MaxFloat32))},
-				equalList(wantFS.Get(6).List()),
+				equalList{wantFS.Get(6).List()},
 			},
 			8: {
 				appendList{V(""), V(""), V(""), V(""), V(""), V("")},
 				lenList(6),
 				setList{0: V("8"), 2: V("eight")},
 				truncList(3),
-				equalList(wantFS.Get(8).List()),
+				equalList{wantFS.Get(8).List()},
 			},
 			10: {
 				appendList{V([]byte(nil)), V([]byte(nil))},
 				setList{0: V([]byte("10"))},
 				appendList{V([]byte("wrong"))},
 				setList{2: V([]byte("ten"))},
-				equalList(wantFS.Get(10).List()),
+				equalList{wantFS.Get(10).List()},
 			},
 			12: {
 				appendList{V("12"), V("wrong"), V("twelve")},
 				setList{1: V("")},
-				equalList(wantFS.Get(12).List()),
+				equalList{wantFS.Get(12).List()},
 			},
 			14: {
 				appendList{V([]byte("14")), V([]byte(nil)), V([]byte("fourteen"))},
-				equalList(wantFS.Get(14).List()),
+				equalList{wantFS.Get(14).List()},
 			},
 			16: {
 				appendList{V("16"), V(""), V("sixteen"), V("extra")},
 				truncList(3),
-				equalList(wantFS.Get(16).List()),
+				equalList{wantFS.Get(16).List()},
 			},
 			18: {
 				appendList{V([]byte("18")), V([]byte(nil)), V([]byte("eighteen"))},
-				equalList(wantFS.Get(18).List()),
+				equalList{wantFS.Get(18).List()},
 			},
 		},
 		hasFields{1: true, 2: true, 3: true, 4: true, 5: true, 6: true, 7: true, 8: true, 9: true, 10: true, 11: true, 12: true, 13: true, 14: true, 15: true, 16: true, 17: true, 18: true, 19: true},
-		equalMessage(want),
-		clearFields{1: true, 2: true, 3: true, 4: true, 5: true, 6: true, 7: true, 8: true, 9: true, 10: true, 11: true, 12: true, 13: true, 14: true, 15: true, 16: true, 17: true, 18: true, 19: true},
-		equalMessage(empty),
+		equalMessage{want},
+		clearFields{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19},
+		equalMessage{empty},
 	})
 }
 
@@ -605,38 +661,38 @@
 			},
 			4: {
 				setMap{uint32(0): V("zero"), uint32(1): V("one"), uint32(2): V("two")},
-				equalMap(wantFS.Get(4).Map()),
+				equalMap{wantFS.Get(4).Map()},
 			},
 			6: {
-				clearMap{"noexist": true},
+				clearMap{"noexist"},
 				setMap{"foo": V("bar")},
 				setMap{"": V("empty")},
 				getMap{"": V("empty"), "foo": V("bar"), "noexist": V(nil)},
 				setMap{"": V(""), "extra": V("extra")},
-				clearMap{"extra": true, "noexist": true},
+				clearMap{"extra", "noexist"},
 			},
 			8: {
-				equalMap(emptyFS.Get(8).Map()),
+				equalMap{emptyFS.Get(8).Map()},
 				setMap{"one": V(int32(1)), "two": V(int32(2)), "three": V(int32(3))},
 			},
 			10: {
 				setMap{"0x00": V(uint32(0x00)), "0xff": V(uint32(0xff)), "0xdead": V(uint32(0xdead))},
 				lenMap(3),
-				equalMap(wantFS.Get(10).Map()),
+				equalMap{wantFS.Get(10).Map()},
 				getMap{"0x00": V(uint32(0x00)), "0xff": V(uint32(0xff)), "0xdead": V(uint32(0xdead)), "0xdeadbeef": V(nil)},
 			},
 			12: {
 				setMap{"nan": V(float32(math.NaN())), "pi": V(float32(math.Pi)), "e": V(float32(math.E))},
-				clearMap{"e": true, "phi": true},
+				clearMap{"e", "phi"},
 				rangeMap{"nan": V(float32(math.NaN())), "pi": V(float32(math.Pi))},
 			},
 			14: {
-				equalMap(emptyFS.Get(14).Map()),
+				equalMap{emptyFS.Get(14).Map()},
 				setMap{"s1": V("s1"), "s2": V("s2")},
 			},
 			16: {
 				setMap{"s1": V([]byte("s1")), "s2": V([]byte("s2"))},
-				equalMap(wantFS.Get(16).Map()),
+				equalMap{wantFS.Get(16).Map()},
 			},
 			18: {
 				hasMap{"s1": false, "s2": false, "s3": false},
@@ -644,7 +700,7 @@
 				hasMap{"s1": true, "s2": true, "s3": false},
 			},
 			20: {
-				equalMap(emptyFS.Get(20).Map()),
+				equalMap{emptyFS.Get(20).Map()},
 				setMap{"s1": V([]byte("s1")), "s2": V([]byte("s2"))},
 			},
 			22: {
@@ -655,69 +711,24 @@
 			},
 			24: {
 				setMap{"s1": V([]byte("s1")), "s2": V([]byte("s2"))},
-				equalMap(wantFS.Get(24).Map()),
+				equalMap{wantFS.Get(24).Map()},
 			},
 		},
 		hasFields{1: true, 2: true, 3: true, 4: true, 5: true, 6: true, 7: true, 8: true, 9: true, 10: true, 11: true, 12: true, 13: true, 14: true, 15: true, 16: true, 17: true, 18: true, 19: true, 20: true, 21: true, 22: true, 23: true, 24: true, 25: true},
-		equalMessage(want),
-		clearFields{1: true, 2: true, 3: true, 4: true, 5: true, 6: true, 7: true, 8: true, 9: true, 10: true, 11: true, 12: true, 13: true, 14: true, 15: true, 16: true, 17: true, 18: true, 19: true, 20: true, 21: true, 22: true, 23: true, 24: true, 25: true},
-		equalMessage(empty),
+		equalMessage{want},
+		clearFields{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25},
+		equalMessage{empty},
 	})
 }
 
-type (
-	OneofScalars struct {
-		Union isOneofScalars_Union `protobuf_oneof:"union"`
-	}
-	isOneofScalars_Union interface {
-		isOneofScalars_Union()
-	}
-
-	OneofScalars_Bool struct {
-		Bool bool `protobuf:"1"`
-	}
-	OneofScalars_Int32 struct {
-		Int32 MyInt32 `protobuf:"2"`
-	}
-	OneofScalars_Int64 struct {
-		Int64 int64 `protobuf:"3"`
-	}
-	OneofScalars_Uint32 struct {
-		Uint32 MyUint32 `protobuf:"4"`
-	}
-	OneofScalars_Uint64 struct {
-		Uint64 uint64 `protobuf:"5"`
-	}
-	OneofScalars_Float32 struct {
-		Float32 MyFloat32 `protobuf:"6"`
-	}
-	OneofScalars_Float64 struct {
-		Float64 float64 `protobuf:"7"`
-	}
-	OneofScalars_String struct {
-		String string `protobuf:"8"`
-	}
-	OneofScalars_StringA struct {
-		StringA []byte `protobuf:"9"`
-	}
-	OneofScalars_StringB struct {
-		StringB MyString `protobuf:"10"`
-	}
-	OneofScalars_Bytes struct {
-		Bytes []byte `protobuf:"11"`
-	}
-	OneofScalars_BytesA struct {
-		BytesA string `protobuf:"12"`
-	}
-	OneofScalars_BytesB struct {
-		BytesB MyBytes `protobuf:"13"`
-	}
-)
+type OneofScalars struct {
+	Union isOneofScalars_Union `protobuf_oneof:"union"`
+}
 
 var oneofScalarsType = MessageType{Type: ptype.GoMessage(
 	mustMakeMessageDesc(ptype.StandaloneMessage{
 		Syntax:   pref.Proto2,
-		FullName: "ScalarProto2",
+		FullName: "OneofScalars",
 		Fields: []ptype.Field{
 			{Name: "f1", Number: 1, Cardinality: pref.Optional, Kind: pref.BoolKind, Default: V(bool(true)), OneofName: "union"},
 			{Name: "f2", Number: 2, Cardinality: pref.Optional, Kind: pref.Int32Kind, Default: V(int32(2)), OneofName: "union"},
@@ -765,6 +776,51 @@
 	}
 }
 
+type (
+	isOneofScalars_Union interface {
+		isOneofScalars_Union()
+	}
+	OneofScalars_Bool struct {
+		Bool bool `protobuf:"1"`
+	}
+	OneofScalars_Int32 struct {
+		Int32 MyInt32 `protobuf:"2"`
+	}
+	OneofScalars_Int64 struct {
+		Int64 int64 `protobuf:"3"`
+	}
+	OneofScalars_Uint32 struct {
+		Uint32 MyUint32 `protobuf:"4"`
+	}
+	OneofScalars_Uint64 struct {
+		Uint64 uint64 `protobuf:"5"`
+	}
+	OneofScalars_Float32 struct {
+		Float32 MyFloat32 `protobuf:"6"`
+	}
+	OneofScalars_Float64 struct {
+		Float64 float64 `protobuf:"7"`
+	}
+	OneofScalars_String struct {
+		String string `protobuf:"8"`
+	}
+	OneofScalars_StringA struct {
+		StringA []byte `protobuf:"9"`
+	}
+	OneofScalars_StringB struct {
+		StringB MyString `protobuf:"10"`
+	}
+	OneofScalars_Bytes struct {
+		Bytes []byte `protobuf:"11"`
+	}
+	OneofScalars_BytesA struct {
+		BytesA string `protobuf:"12"`
+	}
+	OneofScalars_BytesB struct {
+		BytesB MyBytes `protobuf:"13"`
+	}
+)
+
 func (*OneofScalars_Bool) isOneofScalars_Union()    {}
 func (*OneofScalars_Int32) isOneofScalars_Union()   {}
 func (*OneofScalars_Int64) isOneofScalars_Union()   {}
@@ -799,42 +855,273 @@
 		hasFields{1: false, 2: false, 3: false, 4: false, 5: false, 6: false, 7: false, 8: false, 9: false, 10: false, 11: false, 12: false, 13: false},
 		getFields{1: V(bool(true)), 2: V(int32(2)), 3: V(int64(3)), 4: V(uint32(4)), 5: V(uint64(5)), 6: V(float32(6)), 7: V(float64(7)), 8: V(string("8")), 9: V(string("9")), 10: V(string("10")), 11: V([]byte("11")), 12: V([]byte("12")), 13: V([]byte("13"))},
 
-		setFields{1: V(bool(true))}, hasFields{1: true}, equalMessage(want1),
-		setFields{2: V(int32(20))}, hasFields{2: true}, equalMessage(want2),
-		setFields{3: V(int64(30))}, hasFields{3: true}, equalMessage(want3),
-		setFields{4: V(uint32(40))}, hasFields{4: true}, equalMessage(want4),
-		setFields{5: V(uint64(50))}, hasFields{5: true}, equalMessage(want5),
-		setFields{6: V(float32(60))}, hasFields{6: true}, equalMessage(want6),
-		setFields{7: V(float64(70))}, hasFields{7: true}, equalMessage(want7),
-		setFields{8: V(string("80"))}, hasFields{8: true}, equalMessage(want8),
-		setFields{9: V(string("90"))}, hasFields{9: true}, equalMessage(want9),
-		setFields{10: V(string("100"))}, hasFields{10: true}, equalMessage(want10),
-		setFields{11: V([]byte("110"))}, hasFields{11: true}, equalMessage(want11),
-		setFields{12: V([]byte("120"))}, hasFields{12: true}, equalMessage(want12),
-		setFields{13: V([]byte("130"))}, hasFields{13: true}, equalMessage(want13),
+		setFields{1: V(bool(true))}, hasFields{1: true}, equalMessage{want1},
+		setFields{2: V(int32(20))}, hasFields{2: true}, equalMessage{want2},
+		setFields{3: V(int64(30))}, hasFields{3: true}, equalMessage{want3},
+		setFields{4: V(uint32(40))}, hasFields{4: true}, equalMessage{want4},
+		setFields{5: V(uint64(50))}, hasFields{5: true}, equalMessage{want5},
+		setFields{6: V(float32(60))}, hasFields{6: true}, equalMessage{want6},
+		setFields{7: V(float64(70))}, hasFields{7: true}, equalMessage{want7},
+		setFields{8: V(string("80"))}, hasFields{8: true}, equalMessage{want8},
+		setFields{9: V(string("90"))}, hasFields{9: true}, equalMessage{want9},
+		setFields{10: V(string("100"))}, hasFields{10: true}, equalMessage{want10},
+		setFields{11: V([]byte("110"))}, hasFields{11: true}, equalMessage{want11},
+		setFields{12: V([]byte("120"))}, hasFields{12: true}, equalMessage{want12},
+		setFields{13: V([]byte("130"))}, hasFields{13: true}, equalMessage{want13},
 
 		hasFields{1: false, 2: false, 3: false, 4: false, 5: false, 6: false, 7: false, 8: false, 9: false, 10: false, 11: false, 12: false, 13: true},
 		getFields{1: V(bool(true)), 2: V(int32(2)), 3: V(int64(3)), 4: V(uint32(4)), 5: V(uint64(5)), 6: V(float32(6)), 7: V(float64(7)), 8: V(string("8")), 9: V(string("9")), 10: V(string("10")), 11: V([]byte("11")), 12: V([]byte("12")), 13: V([]byte("130"))},
-		clearFields{1: true, 2: true, 3: true, 4: true, 5: true, 6: true, 7: true, 8: true, 9: true, 10: true, 11: true, 12: true},
-		equalMessage(want13),
-		clearFields{13: true},
-		equalMessage(empty),
+		clearFields{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12},
+		equalMessage{want13},
+		clearFields{13},
+		equalMessage{empty},
 	})
 }
 
-// TODO: Need to test singular and repeated messages
+type EnumProto2 int32
+
+var enumProto2Type = ptype.GoEnum(
+	mustMakeEnumDesc(ptype.StandaloneEnum{
+		Syntax:   pref.Proto2,
+		FullName: "EnumProto2",
+		Values:   []ptype.EnumValue{{Name: "DEAD", Number: 0xdead}, {Name: "BEEF", Number: 0xbeef}},
+	}),
+	func(_ pref.EnumType, n pref.EnumNumber) pref.ProtoEnum {
+		return EnumProto2(n)
+	},
+)
+
+func (e EnumProto2) Enum() *EnumProto2       { return &e }
+func (e EnumProto2) Type() pref.EnumType     { return enumProto2Type }
+func (e EnumProto2) Number() pref.EnumNumber { return pref.EnumNumber(e) }
+func (e EnumProto2) ProtoReflect() pref.Enum { return e }
+
+type EnumProto3 int32
+
+var enumProto3Type = ptype.GoEnum(
+	mustMakeEnumDesc(ptype.StandaloneEnum{
+		Syntax:   pref.Proto3,
+		FullName: "EnumProto3",
+		Values:   []ptype.EnumValue{{Name: "ALPHA", Number: 0}, {Name: "BRAVO", Number: 1}},
+	}),
+	func(_ pref.EnumType, n pref.EnumNumber) pref.ProtoEnum {
+		return EnumProto3(n)
+	},
+)
+
+func (e EnumProto3) Enum() *EnumProto3       { return &e }
+func (e EnumProto3) Type() pref.EnumType     { return enumProto3Type }
+func (e EnumProto3) Number() pref.EnumNumber { return pref.EnumNumber(e) }
+func (e EnumProto3) ProtoReflect() pref.Enum { return e }
+
+type EnumMessages struct {
+	EnumP2        *EnumProto2              `protobuf:"1"`
+	EnumP3        *EnumProto3              `protobuf:"2"`
+	MessageLegacy *proto2_20180125.Message `protobuf:"3"`
+	MessageCycle  *EnumMessages            `protobuf:"4"`
+	EnumList      []EnumProto2             `protobuf:"5"`
+	MessageList   []*ScalarProto2          `protobuf:"6"`
+	EnumMap       map[string]EnumProto3    `protobuf:"7"`
+	MessageMap    map[string]*ScalarProto3 `protobuf:"8"`
+	Union         isEnumMessages_Union     `protobuf_oneof:"union"`
+}
+
+var enumMessagesType = MessageType{Type: ptype.GoMessage(
+	mustMakeMessageDesc(ptype.StandaloneMessage{
+		Syntax:   pref.Proto2,
+		FullName: "EnumMessages",
+		Fields: []ptype.Field{
+			{Name: "f1", Number: 1, Cardinality: pref.Optional, Kind: pref.EnumKind, Default: V("BEEF"), EnumType: enumProto2Type},
+			{Name: "f2", Number: 2, Cardinality: pref.Optional, Kind: pref.EnumKind, Default: V("BRAVO"), EnumType: enumProto3Type},
+			{Name: "f3", Number: 3, Cardinality: pref.Optional, Kind: pref.MessageKind, MessageType: MessageOf(new(proto2_20180125.Message)).Type()},
+			{Name: "f4", Number: 4, Cardinality: pref.Optional, Kind: pref.MessageKind, MessageType: ptype.PlaceholderMessage("EnumMessages")},
+			{Name: "f5", Number: 5, Cardinality: pref.Repeated, Kind: pref.EnumKind, EnumType: enumProto2Type},
+			{Name: "f6", Number: 6, Cardinality: pref.Repeated, Kind: pref.MessageKind, MessageType: scalarProto2Type.Type},
+			{Name: "f7", Number: 7, Cardinality: pref.Repeated, Kind: pref.MessageKind, MessageType: enumMapDesc},
+			{Name: "f8", Number: 8, Cardinality: pref.Repeated, Kind: pref.MessageKind, MessageType: messageMapDesc},
+			{Name: "f9", Number: 9, Cardinality: pref.Optional, Kind: pref.EnumKind, Default: V("BEEF"), OneofName: "union", EnumType: enumProto2Type},
+			{Name: "f10", Number: 10, Cardinality: pref.Optional, Kind: pref.EnumKind, Default: V("BRAVO"), OneofName: "union", EnumType: enumProto3Type},
+			{Name: "f11", Number: 11, Cardinality: pref.Optional, Kind: pref.MessageKind, OneofName: "union", MessageType: scalarProto2Type.Type},
+			{Name: "f12", Number: 12, Cardinality: pref.Optional, Kind: pref.MessageKind, OneofName: "union", MessageType: scalarProto3Type.Type},
+		},
+		Oneofs: []ptype.Oneof{{Name: "union"}},
+	}),
+	func(pref.MessageType) pref.ProtoMessage {
+		return new(EnumMessages)
+	},
+)}
+
+var enumMapDesc = mustMakeMessageDesc(ptype.StandaloneMessage{
+	Syntax:   pref.Proto2,
+	FullName: "EnumMessages.F7Entry",
+	Fields: []ptype.Field{
+		{Name: "key", Number: 1, Cardinality: pref.Optional, Kind: pref.StringKind},
+		{Name: "value", Number: 2, Cardinality: pref.Optional, Kind: pref.EnumKind, EnumType: enumProto3Type},
+	},
+	Options: &descriptorV1.MessageOptions{MapEntry: protoV1.Bool(true)},
+})
+
+var messageMapDesc = mustMakeMessageDesc(ptype.StandaloneMessage{
+	Syntax:   pref.Proto2,
+	FullName: "EnumMessages.F8Entry",
+	Fields: []ptype.Field{
+		{Name: "key", Number: 1, Cardinality: pref.Optional, Kind: pref.StringKind},
+		{Name: "value", Number: 2, Cardinality: pref.Optional, Kind: pref.MessageKind, MessageType: scalarProto3Type.Type},
+	},
+	Options: &descriptorV1.MessageOptions{MapEntry: protoV1.Bool(true)},
+})
+
+func (m *EnumMessages) Type() pref.MessageType            { return enumMessagesType.Type }
+func (m *EnumMessages) KnownFields() pref.KnownFields     { return enumMessagesType.KnownFieldsOf(m) }
+func (m *EnumMessages) UnknownFields() pref.UnknownFields { return enumMessagesType.UnknownFieldsOf(m) }
+func (m *EnumMessages) Interface() pref.ProtoMessage      { return m }
+func (m *EnumMessages) ProtoReflect() pref.Message        { return m }
+func (m *EnumMessages) ProtoMutable()                     {}
+
+func (*EnumMessages) XXX_OneofFuncs() (func(protoV1.Message, *protoV1.Buffer) error, func(protoV1.Message, int, int, *protoV1.Buffer) (bool, error), func(protoV1.Message) int, []interface{}) {
+	return nil, nil, nil, []interface{}{
+		(*EnumMessages_OneofE2)(nil),
+		(*EnumMessages_OneofE3)(nil),
+		(*EnumMessages_OneofM2)(nil),
+		(*EnumMessages_OneofM3)(nil),
+	}
+}
+
+type (
+	isEnumMessages_Union interface {
+		isEnumMessages_Union()
+	}
+	EnumMessages_OneofE2 struct {
+		OneofE2 EnumProto2 `protobuf:"9"`
+	}
+	EnumMessages_OneofE3 struct {
+		OneofE3 EnumProto3 `protobuf:"10"`
+	}
+	EnumMessages_OneofM2 struct {
+		OneofM2 *ScalarProto2 `protobuf:"11"`
+	}
+	EnumMessages_OneofM3 struct {
+		OneofM3 *ScalarProto3 `protobuf:"12"`
+	}
+)
+
+func (*EnumMessages_OneofE2) isEnumMessages_Union() {}
+func (*EnumMessages_OneofE3) isEnumMessages_Union() {}
+func (*EnumMessages_OneofM2) isEnumMessages_Union() {}
+func (*EnumMessages_OneofM3) isEnumMessages_Union() {}
+
+func TestEnumMessages(t *testing.T) {
+	// TODO: Test behavior of Get on unpopulated message.
+	wantL := MessageOf(&proto2_20180125.Message{OptionalFloat: protoV1.Float32(math.E)})
+	wantM := &EnumMessages{EnumP2: EnumProto2(1234).Enum()}
+	wantM2a := &ScalarProto2{Float32: protoV1.Float32(math.Pi)}
+	wantM2b := &ScalarProto2{Float32: protoV1.Float32(math.Phi)}
+	wantM3a := &ScalarProto3{Float32: math.Pi}
+	wantM3b := &ScalarProto3{Float32: math.Ln2}
+
+	wantList5 := (&EnumMessages{EnumList: []EnumProto2{333, 222}}).KnownFields().Get(5)
+	wantList6 := (&EnumMessages{MessageList: []*ScalarProto2{wantM2a, wantM2b}}).KnownFields().Get(6)
+
+	wantMap7 := (&EnumMessages{EnumMap: map[string]EnumProto3{"one": 1, "two": 2}}).KnownFields().Get(7)
+	wantMap8 := (&EnumMessages{MessageMap: map[string]*ScalarProto3{"pi": wantM3a, "ln2": wantM3b}}).KnownFields().Get(8)
+
+	testMessage(t, nil, &EnumMessages{}, messageOps{
+		hasFields{1: false, 2: false, 3: false, 4: false, 5: false, 6: false, 7: false, 8: false, 9: false, 10: false, 11: false, 12: false},
+		getFields{1: VE(0xbeef), 2: VE(1), 9: VE(0xbeef), 10: VE(1)},
+
+		// Test singular enums.
+		setFields{1: VE(0xdead), 2: VE(0)},
+		getFields{1: VE(0xdead), 2: VE(0)},
+		hasFields{1: true, 2: true},
+
+		// Test singular messages.
+		messageFields{3: messageOps{setFields{109: V(float32(math.E))}}},
+		messageFields{4: messageOps{setFields{1: VE(1234)}}},
+		getFields{3: V(wantL), 4: V(wantM)},
+		clearFields{3, 4},
+		hasFields{3: false, 4: false},
+		setFields{3: V(wantL), 4: V(wantM)},
+		hasFields{3: true, 4: true},
+
+		// Test list of enums and messages.
+		listFields{
+			5: listOps{
+				appendList{VE(111), VE(222)},
+				setList{0: VE(333)},
+				getList{0: VE(333), 1: VE(222)},
+				lenList(2),
+			},
+			6: listOps{
+				appendMessageList{setFields{4: V(uint32(1e6))}},
+				appendMessageList{setFields{6: V(float32(math.Phi))}},
+				setList{0: V(wantM2a)},
+				getList{0: V(wantM2a), 1: V(wantM2b)},
+			},
+		},
+		getFields{5: wantList5, 6: wantList6},
+		hasFields{5: true, 6: true},
+		listFields{5: listOps{truncList(0)}},
+		hasFields{5: false, 6: true},
+
+		// Test maps of enums and messages.
+		mapFields{
+			7: mapOps{
+				setMap{"one": VE(1), "two": VE(2)},
+				hasMap{"one": true, "two": true, "three": false},
+				lenMap(2),
+			},
+			8: mapOps{
+				messageMap{"pi": messageOps{setFields{6: V(float32(math.Pi))}}},
+				setMap{"ln2": V(wantM3b)},
+				getMap{"pi": V(wantM3a), "ln2": V(wantM3b), "none": V(nil)},
+				lenMap(2),
+			},
+		},
+		getFields{7: wantMap7, 8: wantMap8},
+		hasFields{7: true, 8: true},
+		mapFields{8: mapOps{clearMap{"pi", "ln2", "none"}}},
+		hasFields{7: true, 8: false},
+
+		// Test oneofs of enums and messages.
+		setFields{9: VE(0xdead)},
+		hasFields{1: true, 2: true, 9: true, 10: false, 11: false, 12: false},
+		setFields{10: VE(0)},
+		hasFields{1: true, 2: true, 9: false, 10: true, 11: false, 12: false},
+		messageFields{11: messageOps{setFields{6: V(float32(math.Pi))}}},
+		getFields{11: V(wantM2a)},
+		hasFields{1: true, 2: true, 9: false, 10: false, 11: true, 12: false},
+		messageFields{12: messageOps{setFields{6: V(float32(math.Pi))}}},
+		getFields{12: V(wantM3a)},
+		hasFields{1: true, 2: true, 9: false, 10: false, 11: false, 12: true},
+
+		// Check entire message.
+		rangeFields{1: VE(0xdead), 2: VE(0), 3: V(wantL), 4: V(wantM), 6: wantList6, 7: wantMap7, 12: V(wantM3a)},
+		equalMessage{&EnumMessages{
+			EnumP2:        EnumProto2(0xdead).Enum(),
+			EnumP3:        EnumProto3(0).Enum(),
+			MessageLegacy: &proto2_20180125.Message{OptionalFloat: protoV1.Float32(math.E)},
+			MessageCycle:  wantM,
+			MessageList:   []*ScalarProto2{wantM2a, wantM2b},
+			EnumMap:       map[string]EnumProto3{"one": 1, "two": 2},
+			Union:         &EnumMessages_OneofM3{wantM3a},
+		}},
+		clearFields{1, 2, 3, 4, 6, 7, 12},
+		equalMessage{&EnumMessages{}},
+	})
+}
 
 var cmpOpts = cmp.Options{
-	cmp.Transformer("UnwrapValue", func(v pref.Value) interface{} {
-		return v.Interface()
+	cmp.Comparer(func(x, y *proto2_20180125.Message) bool {
+		return protoV1.Equal(x, y)
 	}),
-	cmp.Transformer("UnwrapList", func(v pref.List) interface{} {
-		return v.(interface{ Unwrap() interface{} }).Unwrap()
+	cmp.Transformer("UnwrapValue", func(pv pref.Value) interface{} {
+		return pv.Interface()
 	}),
-	cmp.Transformer("UnwrapMap", func(m pref.Map) interface{} {
-		return m.(interface{ Unwrap() interface{} }).Unwrap()
+	cmp.Transformer("UnwrapGeneric", func(x pvalue.Unwrapper) interface{} {
+		return x.Unwrap()
 	}),
 	cmpopts.EquateNaNs(),
+	cmpopts.EquateEmpty(),
 }
 
 func testMessage(t *testing.T, p path, m pref.Message, tt messageOps) {
@@ -843,7 +1130,7 @@
 		p.Push(i)
 		switch op := op.(type) {
 		case equalMessage:
-			if diff := cmp.Diff(op, m, cmpOpts); diff != "" {
+			if diff := cmp.Diff(op.Message, m, cmpOpts); diff != "" {
 				t.Errorf("operation %v, message mismatch (-want, +got):\n%s", p, diff)
 			}
 		case hasFields:
@@ -869,10 +1156,14 @@
 				fs.Set(n, v)
 			}
 		case clearFields:
-			for n, ok := range op {
-				if ok {
-					fs.Clear(n)
-				}
+			for _, n := range op {
+				fs.Clear(n)
+			}
+		case messageFields:
+			for n, tt := range op {
+				p.Push(int(n))
+				testMessage(t, p, fs.Mutable(n).(pref.Message), tt)
+				p.Pop()
 			}
 		case listFields:
 			for n, tt := range op {
@@ -886,6 +1177,16 @@
 				testMaps(t, p, fs.Mutable(n).(pref.Map), tt)
 				p.Pop()
 			}
+		case rangeFields:
+			got := map[pref.FieldNumber]pref.Value{}
+			want := map[pref.FieldNumber]pref.Value(op)
+			fs.Range(func(n pref.FieldNumber, v pref.Value) bool {
+				got[n] = v
+				return true
+			})
+			if diff := cmp.Diff(want, got, cmpOpts); diff != "" {
+				t.Errorf("operation %v, KnownFields.Range mismatch (-want, +got):\n%s", p, diff)
+			}
 		default:
 			t.Fatalf("operation %v, invalid operation: %T", p, op)
 		}
@@ -898,7 +1199,7 @@
 		p.Push(i)
 		switch op := op.(type) {
 		case equalList:
-			if diff := cmp.Diff(op, v, cmpOpts); diff != "" {
+			if diff := cmp.Diff(op.List, v, cmpOpts); diff != "" {
 				t.Errorf("operation %v, list mismatch (-want, +got):\n%s", p, diff)
 			}
 		case lenList:
@@ -922,6 +1223,8 @@
 			for _, e := range op {
 				v.Append(e)
 			}
+		case appendMessageList:
+			testMessage(t, p, v.MutableAppend().(pref.Message), messageOps(op))
 		case truncList:
 			v.Truncate(int(op))
 		default:
@@ -936,7 +1239,7 @@
 		p.Push(i)
 		switch op := op.(type) {
 		case equalMap:
-			if diff := cmp.Diff(op, m, cmpOpts); diff != "" {
+			if diff := cmp.Diff(op.Map, m, cmpOpts); diff != "" {
 				t.Errorf("operation %v, map mismatch (-want, +got):\n%s", p, diff)
 			}
 		case lenMap:
@@ -966,10 +1269,12 @@
 				m.Set(V(k).MapKey(), v)
 			}
 		case clearMap:
-			for v, ok := range op {
-				if ok {
-					m.Clear(V(v).MapKey())
-				}
+			for _, k := range op {
+				m.Clear(V(k).MapKey())
+			}
+		case messageMap:
+			for k, tt := range op {
+				testMessage(t, p, m.Mutable(V(k).MapKey()).(pref.Message), tt)
 			}
 		case rangeMap:
 			got := map[interface{}]pref.Value{}