start drawdag_test.go

engine/drawdag_test.go

@@ -0,0 +1,83 @@
+package engine
+
+import (
+	"testing"
+
+	"drjosh.dev/gurgle/geom"
+	"github.com/google/go-cmp/cmp"
+	"github.com/hajimehoshi/ebiten/v2"
+)
+
+type fakeDrawBoxer string
+
+func (fakeDrawBoxer) Draw(*ebiten.Image, *ebiten.DrawImageOptions) {}
+func (fakeDrawBoxer) BoundingBox() geom.Box {
+	return geom.Box{}
+}
+
+func TestDAGAddRemoveEdge(t *testing.T) {
+	d := make(dag)
+	var u, v fakeDrawBoxer = "u", "v"
+	d.addEdge(u, v)
+	want := dag{
+		u: edges{
+			in:  drawerSet{},
+			out: drawerSet{v: {}},
+		},
+		v: edges{
+			in:  drawerSet{u: {}},
+			out: drawerSet{},
+		},
+	}
+	if diff := cmp.Diff(d, want, cmp.AllowUnexported(edges{})); diff != "" {
+		t.Errorf("diff after adding edge (u->v):\n%s", diff)
+	}
+	d.removeEdge(u, v)
+	want = dag{
+		u: edges{
+			in:  drawerSet{},
+			out: drawerSet{},
+		},
+		v: edges{
+			in:  drawerSet{},
+			out: drawerSet{},
+		},
+	}
+	if diff := cmp.Diff(d, want, cmp.AllowUnexported(edges{})); diff != "" {
+		t.Errorf("diff after removing edge (u->v):\n%s", diff)
+	}
+}
+
+func TestDAGAddVertex(t *testing.T) {
+	d := make(dag)
+	u := fakeDrawBoxer("u")
+	d.addVertex(u)
+	want := dag{
+		u: edges{
+			in:  drawerSet{},
+			out: drawerSet{},
+		},
+	}
+	if diff := cmp.Diff(d, want, cmp.AllowUnexported(edges{})); diff != "" {
+		t.Errorf("diff after adding vertex u:\n%s", diff)
+	}
+	v := fakeDrawBoxer("v")
+	d.addVertex(v)
+	want = dag{
+		u: edges{
+			in:  drawerSet{},
+			out: drawerSet{},
+		},
+		v: edges{
+			in:  drawerSet{},
+			out: drawerSet{},
+		},
+	}
+	if diff := cmp.Diff(d, want, cmp.AllowUnexported(edges{})); diff != "" {
+		t.Errorf("diff after adding vertex v:\n%s", diff)
+	}
+	d.addVertex(u)
+	if diff := cmp.Diff(d, want, cmp.AllowUnexported(edges{})); diff != "" {
+		t.Errorf("diff after adding vertex u a second time:\n%s", diff)
+	}
+}