Wrote write goroutine functions.

Refactored subpackages back to root package.

schema_test.go

@@ -0,0 +1,44 @@
+package heartwood
+
+import (
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+func TestNewRelationshipWithValidation(t *testing.T) {
+	cases := []struct {
+		name          string
+		start         *Node
+		end           *Node
+		wantPanic     bool
+		wantPanicText string
+	}{
+		{
+			name:  "valid start and end nodes",
+			start: NewUserNode("pubkey1"),
+			end:   NewEventNode("abc123"),
+		},
+		{
+			name:          "mismatched start node label",
+			start:         NewEventNode("abc123"),
+			end:           NewEventNode("abc123"),
+			wantPanic:     true,
+			wantPanicText: "expected start node to have label \"User\". got [Event]",
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			if tc.wantPanic {
+				assert.PanicsWithError(t, tc.wantPanicText, func() {
+					NewSignedRel(tc.start, tc.end, nil)
+				})
+				return
+			}
+			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")
+		})
+	}
+}