Handle `target: null` the same as `target: ""`.

Closes #1

4 files changed, 85 insertions, 49 deletions

diff --git a/go.mod b/go.mod
index 021c704..7ee6fc0 100644
--- a/go.mod
+++ b/go.mod
@@ -3,9 +3,9 @@ module github.com/Necoro/feed2imap-go
 go 1.14
 
 require (
-	github.com/davecgh/go-spew v1.1.1
 	github.com/emersion/go-imap v1.0.4
 	github.com/emersion/go-message v0.11.3-0.20200422153910-8c6ac6b57e3d
+	github.com/google/go-cmp v0.4.0
 	github.com/mmcdole/gofeed v1.0.0-beta2.0.20200331235650-4298e4366be3
 	gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c
 )
diff --git a/go.sum b/go.sum
index a0a8d0f..6c11df4 100644
--- a/go.sum
+++ b/go.sum
@@ -15,6 +15,8 @@ github.com/emersion/go-sasl v0.0.0-20191210011802-430746ea8b9b h1:uhWtEWBHgop1rq
 github.com/emersion/go-sasl v0.0.0-20191210011802-430746ea8b9b/go.mod h1:G/dpzLu16WtQpBfQ/z3LYiYJn3ZhKSGWn83fyoyQe/k=
 github.com/emersion/go-textwrapper v0.0.0-20160606182133-d0e65e56babe h1:40SWqY0zE3qCi6ZrtTf5OUdNm5lDnGnjRSq9GgmeTrg=
 github.com/emersion/go-textwrapper v0.0.0-20160606182133-d0e65e56babe/go.mod h1:aqO8z8wPrjkscevZJFVE1wXJrLpC5LtJG7fqLOsPb2U=
+github.com/google/go-cmp v0.4.0 h1:xsAVV57WRhGj6kEIi8ReJzQlHHqcBYCElAvkovg3B/4=
+github.com/google/go-cmp v0.4.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/martinlindhe/base36 v1.0.0 h1:eYsumTah144C0A8P1T/AVSUk5ZoLnhfYFM3OGQxB52A=
 github.com/martinlindhe/base36 v1.0.0/go.mod h1:+AtEs8xrBpCeYgSLoY/aJ6Wf37jtBuR0s35750M27+8=
 github.com/mmcdole/gofeed v1.0.0-beta2.0.20200331235650-4298e4366be3 h1:Wy+ed15cpwtLcJYNiO4Z0wmjZHpNj4q0RsGbsoxWSMA=
@@ -36,6 +38,8 @@ golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.2 h1:tW2bmiBqwgJj/UpqtC8EpXEZVYOwU0yG4iWbprSVAcs=
 golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
diff --git a/pkg/config/yaml.go b/pkg/config/yaml.go
index 84f4af6..6d48099 100644
--- a/pkg/config/yaml.go
+++ b/pkg/config/yaml.go
@@ -6,6 +6,12 @@ import (
 	"gopkg.in/yaml.v3"
 )
 
+const (
+	strTag   = "!!str"
+	nullTag  = "!!null"
+	emptyTag = ""
+)
+
 type config struct {
 	*Config      `yaml:",inline"`
 	GlobalConfig Map `yaml:",inline"` // need to be duplicated, because the Map in Config is not filled
@@ -18,7 +24,7 @@ type group struct {
 }
 
 type configGroupFeed struct {
-	Target *string
+	Target yaml.Node
 	Feed   Feed  `yaml:",inline"`
 	Group  group `yaml:",inline"`
 }
@@ -32,9 +38,18 @@ func (grpFeed *configGroupFeed) isFeed() bool {
 }
 
 func (grpFeed *configGroupFeed) target() string {
-	if grpFeed.Target != nil {
-		return *grpFeed.Target
+	tag := grpFeed.Target.ShortTag()
+	switch tag {
+	case strTag:
+		return grpFeed.Target.Value
+	case nullTag:
+		return ""
+	case emptyTag:
+		// tag not set: continue on
+	default:
+		panic("unexpected tag " + tag + " for target node")
 	}
+
 	if grpFeed.Feed.Name != "" {
 		return grpFeed.Feed.Name
 	}
@@ -89,13 +104,13 @@ func appTarget(target []string, app string) []string {
 	}
 }
 
-// Fetch the group structure and populate the `Target` fields in the feeds
+// Fetch the group structure and populate the `targetStr` fields in the feeds
 func buildFeeds(cfg []configGroupFeed, target []string, feeds Feeds) error {
 	for _, f := range cfg {
 		target := appTarget(target, f.target())
 		switch {
 		case f.isFeed() && f.isGroup():
-			return fmt.Errorf("Entry with Target %s is both a Feed and a group", target)
+			return fmt.Errorf("Entry with targetStr %s is both a Feed and a group", target)
 
 		case f.isFeed():
 			feedCopy := f.Feed
diff --git a/pkg/config/yaml_test.go b/pkg/config/yaml_test.go
index 40ee325..575927f 100644
--- a/pkg/config/yaml_test.go
+++ b/pkg/config/yaml_test.go
@@ -1,22 +1,25 @@
 package config
 
 import (
-	"reflect"
 	"strings"
 	"testing"
 
-	"github.com/davecgh/go-spew/spew"
+	"github.com/google/go-cmp/cmp"
+	"gopkg.in/yaml.v3"
 )
 
-func i(i int) *int       { return &i }
-func s(s string) *string { return &s }
-func b(b bool) *bool     { return &b }
+func i(i int) *int   { return &i }
+func b(b bool) *bool { return &b }
 func t(s string) []string {
 	if s == "" {
 		return []string{}
 	}
 	return strings.Split(s, ".")
 }
+func n(s string) (n yaml.Node) {
+	n.SetString(s)
+	return
+}
 
 func TestBuildFeeds(tst *testing.T) {
 	tests := []struct {
@@ -29,45 +32,51 @@ func TestBuildFeeds(tst *testing.T) {
 		{name: "Empty input", wantErr: false, target: "", feeds: nil, result: Feeds{}},
 		{name: "Empty Feed", wantErr: true, target: "",
 			feeds: []configGroupFeed{
-				{Target: s("foo"), Feed: Feed{Url: "google.de"}},
+				{Target: n("foo"), Feed: Feed{Url: "google.de"}},
 			}, result: Feeds{}},
 		{name: "Empty Feed", wantErr: true, target: "",
 			feeds: []configGroupFeed{
-				{Target: nil, Feed: Feed{Url: "google.de"}},
+				{Feed: Feed{Url: "google.de"}},
 			}, result: Feeds{}},
 		{name: "Duplicate Feed Name", wantErr: true, target: "",
 			feeds: []configGroupFeed{
-				{Target: nil, Feed: Feed{Name: "Dup"}},
-				{Target: nil, Feed: Feed{Name: "Dup"}},
+				{Feed: Feed{Name: "Dup"}},
+				{Feed: Feed{Name: "Dup"}},
 			}, result: Feeds{}},
 		{name: "Simple", wantErr: false, target: "",
 			feeds: []configGroupFeed{
-				{Target: s("foo"), Feed: Feed{Name: "muh"}},
+				{Target: n("foo"), Feed: Feed{Name: "muh"}},
 			},
 			result: Feeds{"muh": &Feed{Name: "muh", Target: t("foo")}},
 		},
 		{name: "Simple With Target", wantErr: false, target: "moep",
 			feeds: []configGroupFeed{
-				{Target: s("foo"), Feed: Feed{Name: "muh"}},
+				{Target: n("foo"), Feed: Feed{Name: "muh"}},
 			},
 			result: Feeds{"muh": &Feed{Name: "muh", Target: t("moep.foo")}},
 		},
-		{name: "Simple With Nil Target", wantErr: false, target: "moep",
+		{name: "Simple Without Target", wantErr: false, target: "moep",
 			feeds: []configGroupFeed{
-				{Target: nil, Feed: Feed{Name: "muh"}},
+				{Feed: Feed{Name: "muh"}},
 			},
 			result: Feeds{"muh": &Feed{Name: "muh", Target: t("moep.muh")}},
 		},
+		{name: "Simple With Nil Target", wantErr: false, target: "moep",
+			feeds: []configGroupFeed{
+				{Target: yaml.Node{Tag: "!!null"}, Feed: Feed{Name: "muh"}},
+			},
+			result: Feeds{"muh": &Feed{Name: "muh", Target: t("moep")}},
+		},
 		{name: "Simple With Empty Target", wantErr: false, target: "moep",
 			feeds: []configGroupFeed{
-				{Target: s(""), Feed: Feed{Name: "muh"}},
+				{Target: n(""), Feed: Feed{Name: "muh"}},
 			},
 			result: Feeds{"muh": &Feed{Name: "muh", Target: t("moep")}},
 		},
 		{name: "Multiple Feeds", wantErr: false, target: "moep",
 			feeds: []configGroupFeed{
-				{Target: s("foo"), Feed: Feed{Name: "muh"}},
-				{Target: nil, Feed: Feed{Name: "bar"}},
+				{Target: n("foo"), Feed: Feed{Name: "muh"}},
+				{Feed: Feed{Name: "bar"}},
 			},
 			result: Feeds{
 				"muh": &Feed{Name: "muh", Target: t("moep.foo")},
@@ -76,16 +85,16 @@ func TestBuildFeeds(tst *testing.T) {
 		},
 		{name: "Empty Group", wantErr: false, target: "",
 			feeds: []configGroupFeed{
-				{Target: nil, Group: group{Group: "G1"}},
+				{Group: group{Group: "G1"}},
 			},
 			result: Feeds{},
 		},
 		{name: "Simple Group", wantErr: false, target: "",
 			feeds: []configGroupFeed{
-				{Target: nil, Group: group{Group: "G1", Feeds: []configGroupFeed{
-					{Target: s("bar"), Feed: Feed{Name: "F1"}},
-					{Target: s(""), Feed: Feed{Name: "F2"}},
-					{Target: nil, Feed: Feed{Name: "F3"}},
+				{Group: group{Group: "G1", Feeds: []configGroupFeed{
+					{Target: n("bar"), Feed: Feed{Name: "F1"}},
+					{Target: n(""), Feed: Feed{Name: "F2"}},
+					{Feed: Feed{Name: "F3"}},
 				}}},
 			},
 			result: Feeds{
@@ -96,14 +105,14 @@ func TestBuildFeeds(tst *testing.T) {
 		},
 		{name: "Nested Groups", wantErr: false, target: "",
 			feeds: []configGroupFeed{
-				{Target: nil, Group: group{Group: "G1", Feeds: []configGroupFeed{
-					{Target: nil, Feed: Feed{Name: "F0"}},
-					{Target: s("bar"), Group: group{Group: "G2",
-						Feeds: []configGroupFeed{{Target: nil, Feed: Feed{Name: "F1"}}}}},
-					{Target: s(""), Group: group{Group: "G3",
-						Feeds: []configGroupFeed{{Target: s("baz"), Feed: Feed{Name: "F2"}}}}},
-					{Target: nil, Group: group{Group: "G4",
-						Feeds: []configGroupFeed{{Target: nil, Feed: Feed{Name: "F3"}}}}},
+				{Group: group{Group: "G1", Feeds: []configGroupFeed{
+					{Feed: Feed{Name: "F0"}},
+					{Target: n("bar"), Group: group{Group: "G2",
+						Feeds: []configGroupFeed{{Feed: Feed{Name: "F1"}}}}},
+					{Target: n(""), Group: group{Group: "G3",
+						Feeds: []configGroupFeed{{Target: n("baz"), Feed: Feed{Name: "F2"}}}}},
+					{Group: group{Group: "G4",
+						Feeds: []configGroupFeed{{Feed: Feed{Name: "F3"}}}}},
 				}}},
 			},
 			result: Feeds{
@@ -122,8 +131,8 @@ func TestBuildFeeds(tst *testing.T) {
 				tst.Errorf("buildFeeds() error = %v, wantErr %v", err, tt.wantErr)
 				return
 			}
-			if !tt.wantErr && !reflect.DeepEqual(feeds, tt.result) {
-				tst.Errorf("buildFeeds() got: %s\nwant: %s", spew.Sdump(feeds), spew.Sdump(tt.result))
+			if diff := cmp.Diff(feeds, tt.result); !tt.wantErr && diff != "" {
+				tst.Error(diff)
 			}
 		})
 	}
@@ -180,7 +189,7 @@ feeds:
 `,
 			wantErr: false,
 			config: defaultConfig([]configGroupFeed{
-				{Target: s("bar"), Feed: Feed{
+				{Target: n("bar"), Feed: Feed{
 					Name: "Foo",
 					Url:  "whatever",
 					Options: Options{
@@ -202,7 +211,7 @@ feeds:
 `,
 			wantErr: false,
 			config: defaultConfig([]configGroupFeed{
-				{Target: nil, Feed: Feed{
+				{Feed: Feed{
 					Name: "Foo",
 					Url:  "whatever",
 					Options: Options{
@@ -210,7 +219,7 @@ feeds:
 						InclImages: nil,
 					},
 				}},
-				{Target: s("bla"), Feed: Feed{
+				{Target: n("bla"), Feed: Feed{
 					Name: "Shrubbery",
 					Url:  "google.de",
 					Options: Options{
@@ -227,7 +236,7 @@ feeds:
      target: bla
 `,
 			wantErr: false,
-			config:  defaultConfig([]configGroupFeed{{Target: s("bla"), Group: group{"Foo", nil}}}, nil),
+			config:  defaultConfig([]configGroupFeed{{Target: n("bla"), Group: group{"Foo", nil}}}, nil),
 		},
 		{name: "Feeds and Groups",
 			inp: `
@@ -247,27 +256,31 @@ feeds:
 `,
 			wantErr: false,
 			config: defaultConfig([]configGroupFeed{
-				{Target: nil, Feed: Feed{
+				{Feed: Feed{
 					Name: "Foo",
 					Url:  "whatever",
 				}},
-				{Target: s("target"), Group: group{
+				{Target: n("target"), Group: group{
 					Group: "G1",
 					Feeds: []configGroupFeed{
-						{Target: s(""), Group: group{
+						{Target: n(""), Group: group{
 							Group: "G2",
 							Feeds: []configGroupFeed{
-								{Target: nil, Feed: Feed{Name: "F1", Url: "google.de"}},
+								{Feed: Feed{Name: "F1", Url: "google.de"}},
 							}},
 						},
-						{Target: nil, Feed: Feed{Name: "F2"}},
-						{Target: nil, Group: group{Group: "G3"}},
+						{Feed: Feed{Name: "F2"}},
+						{Group: group{Group: "G3"}},
 					}},
 				},
 			}, nil),
 		},
 	}
 
+	eqNode := cmp.Comparer(func(l, r yaml.Node) bool {
+		return l.Tag == r.Tag && l.Value == r.Value
+	})
+
 	for _, tt := range tests {
 		tst.Run(tt.name, func(tst *testing.T) {
 			var buf = []byte(tt.inp)
@@ -276,8 +289,12 @@ feeds:
 				tst.Errorf("parse() error = %v, wantErr %v", err, tt.wantErr)
 				return
 			}
-			if err == nil && !reflect.DeepEqual(got, tt.config) {
-				tst.Errorf("parse() got: %s\nwant: %s", spew.Sdump(got), spew.Sdump(tt.config))
+
+			if err == nil {
+				diff := cmp.Diff(got, tt.config, eqNode)
+				if diff != "" {
+					tst.Error(diff)
+				}
 			}
 		})
 	}