TestUnmarshalJSON doesn't test the function it describes

[rootulp]

Context

rsmt2d/extendeddatasquare_test.go

Lines 114 to 175 in bb5e119

	// TestUnmarshalJSON test the UnmarshalJSON function.
	func TestUnmarshalJSON(t *testing.T) {
	treeName := "testing_unmarshalJSON_tree"
	treeConstructorFn := sudoConstructorFn
	err := RegisterTree(treeName, treeConstructorFn)
	require.NoError(t, err)
	codec := NewLeoRSCodec()
	result, err := ComputeExtendedDataSquare([][]byte{
	ones, twos,
	threes, fours,
	}, codec, treeConstructorFn)
	if err != nil {
	panic(err)
	}
	tests := []struct {
	name string
	malleate func()
	expectedTreeName string
	cleanUp func()
	}{
	{
	"Tree field exists",
	func() {},
	treeName,
	func() {
	cleanUp(treeName)
	},
	},
	{
	"Tree field missing",
	func() {
	// clear the tree name value in the eds before marshal
	result.treeName = ""
	},
	DefaultTreeName,
	func() {},
	},
	}
	for _, test := range tests {
	t.Run(test.name, func(t *testing.T) {
	test.malleate()
	edsBytes, err := json.Marshal(result)
	if err != nil {
	t.Errorf("failed to marshal EDS: %v", err)
	}
	var eds ExtendedDataSquare
	err = json.Unmarshal(edsBytes, &eds)
	if err != nil {
	t.Errorf("failed to unmarshal EDS: %v", err)
	}
	if !reflect.DeepEqual(result.squareRow, eds.squareRow) {
	t.Errorf("eds not equal after json marshal/unmarshal")
	}
	require.Equal(t, test.expectedTreeName, eds.treeName)
	test.cleanUp()
	})
	}
	}

Problem

This test should be testing the behavior of UnmarshalJSON but it never invokes UnmarshalJSON.

Proposal

Update the test to invoke the function UnmarshalJSON

rsmt2d/extendeddatasquare.go

Lines 34 to 62 in bb5e119

	func (eds *ExtendedDataSquare) UnmarshalJSON(b []byte) error {
	var aux struct {
	DataSquare [][]byte `json:"data_square"`
	Codec string `json:"codec"`
	Tree string `json:"tree"`
	}
	err := json.Unmarshal(b, &aux)
	if err != nil {
	return err
	}
	var treeConstructor TreeConstructorFn
	if aux.Tree == "" {
	aux.Tree = DefaultTreeName
	}
	treeConstructor, err = TreeFn(aux.Tree)
	if err != nil {
	return err
	}
	importedEds, err := ImportExtendedDataSquare(aux.DataSquare, codecs[aux.Codec], treeConstructor)
	if err != nil {
	return err
	}
	*eds = *importedEds
	return nil
	}

[rootulp]

Closed by #287