Wrote simple event to subgraph function.

Updated related code to align.

event.go

@@ -0,0 +1,61 @@
+package heartwood
+
+import (
+	roots "git.wisehodl.dev/jay/go-roots/events"
+)
+
+func EventToSubgraph(e roots.Event) *Subgraph {
+	subgraph := NewSubgraph()
+
+	// Create Event node
+	eventNode := NewEventNode(e.ID)
+	eventNode.Props["created_at"] = e.CreatedAt
+	eventNode.Props["kind"] = e.Kind
+	eventNode.Props["content"] = e.Content
+
+	// Create User node
+	userNode := NewUserNode(e.PubKey)
+
+	// Create SIGNED rel
+	signedRel := NewSignedRel(userNode, eventNode, nil)
+
+	// Create Tag nodes
+	tagNodes := []*Node{}
+	for _, tag := range e.Tags {
+		if !isValidTag(tag) {
+			continue
+		}
+		tagNodes = append(tagNodes, NewTagNode(tag[0], tag[1]))
+	}
+
+	// Create Tag rels
+	tagRels := []*Relationship{}
+	for _, tagNode := range tagNodes {
+		tagRels = append(tagRels, NewTaggedRel(eventNode, tagNode, nil))
+	}
+
+	// Populate subgraph
+	subgraph.AddNode(eventNode)
+	subgraph.AddNode(userNode)
+	subgraph.AddRel(signedRel)
+	for _, node := range tagNodes {
+		subgraph.AddNode(node)
+	}
+	for _, rel := range tagRels {
+		subgraph.AddRel(rel)
+	}
+
+	return subgraph
+}
+
+func isValidTag(t roots.Tag) bool {
+	if len(t) < 2 {
+		// Skip tags that do not have name and value fields
+		return false
+	}
+	if len(t[0])+len(t[1]) > 8192 {
+		// Skip tags that are too large for the neo4j indexer
+		return false
+	}
+	return true
+}

event_test.go

@@ -0,0 +1,204 @@
+package heartwood
+
+import (
+	"fmt"
+	roots "git.wisehodl.dev/jay/go-roots/events"
+	"github.com/stretchr/testify/assert"
+	"reflect"
+	"testing"
+)
+
+var ids = map[string]string{
+	"a": "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
+	"b": "bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb",
+	"c": "cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc",
+	"d": "dddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd",
+}
+
+var static = roots.Event{
+	CreatedAt: 1000,
+	Kind:      1,
+	Content:   "hello",
+}
+
+func newFullEventNode(id string, createdAt, kind int, content string) *Node {
+	n := NewEventNode(id)
+	n.Props["created_at"] = createdAt
+	n.Props["kind"] = kind
+	n.Props["content"] = content
+	return n
+}
+
+func baseSubgraph(eventID, pubkey string) (*Subgraph, *Node, *Node) {
+	s := NewSubgraph()
+	eventNode := newFullEventNode(eventID, static.CreatedAt, static.Kind, static.Content)
+	userNode := NewUserNode(pubkey)
+	s.AddNode(eventNode)
+	s.AddNode(userNode)
+	s.AddRel(NewSignedRel(userNode, eventNode, nil))
+	return s, eventNode, userNode
+}
+
+func TestEventToSubgraph(t *testing.T) {
+	cases := []struct {
+		name     string
+		event    roots.Event
+		expected *Subgraph
+	}{
+		{
+			name: "bare event",
+			event: roots.Event{
+				ID: ids["a"], PubKey: ids["b"],
+				CreatedAt: static.CreatedAt, Kind: static.Kind, Content: static.Content,
+			},
+			expected: func() *Subgraph {
+				s, _, _ := baseSubgraph(ids["a"], ids["b"])
+				return s
+			}(),
+		},
+		{
+			name: "single generic tag",
+			event: roots.Event{
+				ID: ids["a"], PubKey: ids["b"],
+				CreatedAt: static.CreatedAt, Kind: static.Kind, Content: static.Content,
+				Tags: []roots.Tag{{"t", "bitcoin"}},
+			},
+			expected: func() *Subgraph {
+				s, eventNode, _ := baseSubgraph(ids["a"], ids["b"])
+				tagNode := NewTagNode("t", "bitcoin")
+				s.AddNode(tagNode)
+				s.AddRel(NewTaggedRel(eventNode, tagNode, nil))
+				return s
+			}(),
+		},
+		{
+			name: "tag with fewer than 2 elements",
+			event: roots.Event{
+				ID: ids["a"], PubKey: ids["b"],
+				CreatedAt: static.CreatedAt, Kind: static.Kind, Content: static.Content,
+				Tags: []roots.Tag{{"t"}},
+			},
+			expected: func() *Subgraph {
+				s, _, _ := baseSubgraph(ids["a"], ids["b"])
+				return s
+			}(),
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			got := EventToSubgraph(tc.event)
+			assertSubgraphsEqual(t, tc.expected, got)
+		})
+	}
+}
+
+// helpers
+
+func nodesEqual(expected, got *Node) error {
+	// Compare label counts
+	if expected.Labels.Length() != got.Labels.Length() {
+		return fmt.Errorf(
+			"number of labels does not match. expected %d, got %d",
+			expected.Labels.Length(), got.Labels.Length())
+	}
+
+	// Compare label values
+	for _, label := range expected.Labels.ToArray() {
+		if !got.Labels.Contains(label) {
+			return fmt.Errorf("missing label %q", label)
+		}
+	}
+
+	// Compare property values
+	if err := propsEqual(expected.Props, got.Props); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func relsEqual(expected, got *Relationship) error {
+	// Compare type
+	if expected.Type != got.Type {
+		return fmt.Errorf("type: expected %q, got %q", expected.Type, got.Type)
+	}
+
+	// Compare property values
+	if err := propsEqual(expected.Props, got.Props); err != nil {
+		return err
+	}
+
+	// Compare endpoints
+	if err := nodesEqual(expected.Start, got.Start); err != nil {
+		return fmt.Errorf("start node: %w", err)
+	}
+	if err := nodesEqual(expected.End, got.End); err != nil {
+		return fmt.Errorf("end node: %w", err)
+	}
+
+	return nil
+}
+
+func propsEqual(expected, got Properties) error {
+	if len(expected) != len(got) {
+		return fmt.Errorf(
+			"number of props does not match. expected %d, got %d",
+			len(expected), len(got))
+	}
+
+	for key, expectedVal := range expected {
+		gotVal, exists := got[key]
+		if !exists {
+			return fmt.Errorf("missing prop %q", key)
+		}
+		if !reflect.DeepEqual(expectedVal, gotVal) {
+			return fmt.Errorf("prop %q: expected %v, got %v", key, expectedVal, gotVal)
+		}
+	}
+	return nil
+}
+
+func assertSubgraphsEqual(t *testing.T, expected, got *Subgraph) {
+	t.Helper()
+
+	gotNodes := make([]*Node, len(got.Nodes()))
+	copy(gotNodes, got.Nodes())
+
+	gotRels := make([]*Relationship, len(got.Rels()))
+	copy(gotRels, got.Rels())
+
+	for _, expectedNode := range expected.Nodes() {
+		index := findInList(expectedNode, gotNodes, nodesEqual)
+		if index == -1 {
+			assert.Fail(t, fmt.Sprintf("missing expected node: %+v", expectedNode))
+			continue
+		}
+		gotNodes = removeFromList(index, gotNodes)
+	}
+
+	for _, expectedRel := range expected.Rels() {
+		index := findInList(expectedRel, gotRels, relsEqual)
+		if index == -1 {
+			assert.Fail(t, fmt.Sprintf("missing expected rel: %+v", expectedRel))
+			continue
+		}
+		gotRels = removeFromList(index, gotRels)
+	}
+
+	assert.Empty(t, gotNodes, "unexpected nodes in subgraph")
+	assert.Empty(t, gotRels, "unexpected rels in subgraph")
+}
+
+func findInList[T any](item *T, list []*T, equal func(*T, *T) error) int {
+	for i, candidate := range list {
+		if equal(item, candidate) == nil {
+			return i
+		}
+	}
+	return -1
+}
+
+func removeFromList[T any](i int, list []*T) []*T {
+	return append(list[:i], list[i+1:]...)
+}

graph.go

@@ -191,6 +191,14 @@ func (s *Subgraph) AddRel(rel *Relationship) {
 	s.rels = append(s.rels, rel)
 }
 
+func (s *Subgraph) Nodes() []*Node {
+	return s.nodes
+}
+
+func (s *Subgraph) Rels() []*Relationship {
+	return s.rels
+}
+
 // ========================================
 // Structured Subgraph
 // ========================================

graph_test.go

@@ -161,7 +161,7 @@ func TestStructuredSubgraphAddRel(t *testing.T) {
 
 	userNode := NewUserNode("pubkey1")
 	eventNode := NewEventNode("abc123")
-	rel, _ := NewSignedRel(userNode, eventNode, nil)
+	rel := NewSignedRel(userNode, eventNode, nil)
 
 	err := subgraph.AddRel(rel)
 

schema.go

@@ -40,11 +40,10 @@ func NewEventNode(id string) *Node {
 	return NewNode("Event", Properties{"id": id})
 }
 
-func NewTagNode(name string, value string, rest []string) *Node {
+func NewTagNode(name string, value string) *Node {
 	return NewNode("Tag", Properties{
 		"name":  name,
-		"value": value,
-		"rest":  rest})
+		"value": value})
 }
 
 // ========================================
@@ -52,26 +51,26 @@ func NewTagNode(name string, value string, rest []string) *Node {
 // ========================================
 
 func NewSignedRel(
-	start *Node, end *Node, props Properties) (*Relationship, error) {
+	start *Node, end *Node, props Properties) *Relationship {
 	return NewRelationshipWithValidation(
 		"SIGNED", "User", "Event", start, end, props)
 
 }
 
 func NewTaggedRel(
-	start *Node, end *Node, props Properties) (*Relationship, error) {
+	start *Node, end *Node, props Properties) *Relationship {
 	return NewRelationshipWithValidation(
 		"TAGGED", "Event", "Tag", start, end, props)
 }
 
 func NewReferencesEventRel(
-	start *Node, end *Node, props Properties) (*Relationship, error) {
+	start *Node, end *Node, props Properties) *Relationship {
 	return NewRelationshipWithValidation(
 		"REFERENCES", "Tag", "Event", start, end, props)
 }
 
 func NewReferencesUserRel(
-	start *Node, end *Node, props Properties) (*Relationship, error) {
+	start *Node, end *Node, props Properties) *Relationship {
 	return NewRelationshipWithValidation(
 		"REFERENCES", "Tag", "User", start, end, props)
 }
@@ -80,15 +79,13 @@ func NewReferencesUserRel(
 // Relationship Constructor Helpers
 // ========================================
 
-func validateNodeLabel(node *Node, role string, expectedLabel string) error {
+func validateNodeLabel(node *Node, role string, expectedLabel string) {
 	if !node.Labels.Contains(expectedLabel) {
-		return fmt.Errorf(
-			"expected %s node to have label '%s'. got %v",
+		panic(fmt.Errorf(
+			"expected %s node to have label %q. got %v",
 			role, expectedLabel, node.Labels.ToArray(),
-		)
+		))
 	}
-
-	return nil
 }
 
 func NewRelationshipWithValidation(
@@ -97,20 +94,12 @@ func NewRelationshipWithValidation(
 	endLabel string,
 	start *Node,
 	end *Node,
-	props Properties) (*Relationship, error) {
-	var err error
+	props Properties) *Relationship {
 
-	err = validateNodeLabel(start, "start", startLabel)
-	if err != nil {
-		return nil, err
-	}
+	validateNodeLabel(start, "start", startLabel)
+	validateNodeLabel(end, "end", endLabel)
 
-	err = validateNodeLabel(end, "end", endLabel)
-	if err != nil {
-		return nil, err
-	}
-
-	return NewRelationship(rtype, start, end, props), nil
+	return NewRelationship(rtype, start, end, props)
 }
 
 // ========================================

schema_test.go

@@ -10,8 +10,8 @@ func TestNewRelationshipWithValidation(t *testing.T) {
 		name          string
 		start         *Node
 		end           *Node
-		wantErr     bool
-		wantErrText string
+		wantPanic     bool
+		wantPanicText string
 	}{
 		{
 			name:  "valid start and end nodes",
@@ -22,21 +22,20 @@ func TestNewRelationshipWithValidation(t *testing.T) {
 			name:          "mismatched start node label",
 			start:         NewEventNode("abc123"),
 			end:           NewEventNode("abc123"),
-			wantErr:     true,
-			wantErrText: "expected start node to have label 'User'",
+			wantPanic:     true,
+			wantPanicText: "expected start node to have label \"User\". got [Event]",
 		},
 	}
 
 	for _, tc := range cases {
 		t.Run(tc.name, func(t *testing.T) {
-			rel, err := NewSignedRel(tc.start, tc.end, nil)
-			if tc.wantErr {
-				assert.Error(t, err)
-				assert.ErrorContains(t, err, tc.wantErrText)
-				assert.Nil(t, rel)
+			if tc.wantPanic {
+				assert.PanicsWithError(t, tc.wantPanicText, func() {
+					NewSignedRel(tc.start, tc.end, nil)
+				})
 				return
 			}
-			assert.NoError(t, err)
+			rel := NewSignedRel(tc.start, tc.end, nil)
 			assert.Equal(t, "SIGNED", rel.Type)
 			assert.Contains(t, rel.Start.Labels.ToArray(), "User")
 			assert.Contains(t, rel.End.Labels.ToArray(), "Event")

util.go

@@ -29,6 +29,22 @@ func (s Set[T]) Contains(item T) bool {
 	return exists
 }
 
+func (s Set[T]) Equal(other Set[T]) bool {
+	if len(s.inner) != len(other.inner) {
+		return false
+	}
+	for item := range s.inner {
+		if !other.Contains(item) {
+			return false
+		}
+	}
+	return true
+}
+
+func (s Set[T]) Length() int {
+	return len(s.inner)
+}
+
 func (s Set[T]) ToArray() []T {
 	array := []T{}
 	for i := range s.inner {