diff --git a/tests/test_vnf.scad b/tests/test_vnf.scad
new file mode 100644
index 0000000..52da3fb
--- /dev/null
+++ b/tests/test_vnf.scad
@@ -0,0 +1,103 @@
+include <BOSL2/std.scad>
+include <BOSL2/vnf.scad>
+
+
+module test_is_vnf() {
+	assert(is_vnf([[],[]]));
+	assert(!is_vnf([]));
+	assert(is_vnf([[[-1,-1,-1],[1,-1,-1],[0,1,-1],[0,0,1]],[[0,1,2],[0,3,1],[1,3,2],[2,3,0]]]));
+}
+test_is_vnf();
+
+
+module test_is_vnf_list() {
+	assert(is_vnf_list([]));
+	assert(!is_vnf_list([[],[]]));
+	assert(is_vnf_list([[[],[]]]));
+	assert(!is_vnf_list([[[-1,-1,-1],[1,-1,-1],[0,1,-1],[0,0,1]],[[0,1,2],[0,3,1],[1,3,2],[2,3,0]]]));
+	assert(is_vnf_list([[[[-1,-1,-1],[1,-1,-1],[0,1,-1],[0,0,1]],[[0,1,2],[0,3,1],[1,3,2],[2,3,0]]]]));
+}
+test_is_vnf_list();
+
+
+module test_vnf_vertices() {
+	vnf = [[[-1,-1,-1],[1,-1,-1],[0,1,-1],[0,0,1]],[[0,1,2],[0,3,1],[1,3,2],[2,3,0]]];
+	assert(vnf_vertices(vnf) == vnf[0]);
+}
+test_vnf_vertices();
+
+
+module test_vnf_faces() {
+	vnf = [[[-1,-1,-1],[1,-1,-1],[0,1,-1],[0,0,1]],[[0,1,2],[0,3,1],[1,3,2],[2,3,0]]];
+	assert(vnf_faces(vnf) == vnf[1]);
+}
+test_vnf_faces();
+
+
+module test_vnf_get_vertex() {
+	vnf = [[[-1,-1,-1],[1,-1,-1],[0,1,-1],[0,0,1]],[[0,1,2],[0,3,1],[1,3,2],[2,3,0]]];
+	assert(vnf_get_vertex(vnf,[0,1,-1]) == [2,vnf]);
+	assert(vnf_get_vertex(vnf,[0,1,2]) == [4,[concat(vnf[0],[[0,1,2]]),vnf[1]]]);
+}
+test_vnf_get_vertex();
+
+
+module test_vnf_add_face() {
+	verts = [[-1,-1,-1],[1,-1,-1],[0,1,-1],[0,0,1]];
+	faces = [[0,1,2],[0,3,1],[1,3,2],[2,3,0]];
+	vnf1 = vnf_add_face(pts=select(verts,faces[0]));
+	vnf2 = vnf_add_face(vnf1, pts=select(verts,faces[1]));
+	vnf3 = vnf_add_face(vnf2, pts=select(verts,faces[2]));
+	vnf4 = vnf_add_face(vnf3, pts=select(verts,faces[3]));
+	assert(vnf1 == [select(verts,0,2),select(faces,[0])]);
+	assert(vnf2 == [verts,select(faces,[0:1])]);
+	assert(vnf3 == [verts,select(faces,[0:2])]);
+	assert(vnf4 == [verts,faces]);
+}
+test_vnf_add_face();
+
+
+module test_vnf_add_faces() {
+	verts = [[-1,-1,-1],[1,-1,-1],[0,1,-1],[0,0,1]];
+	faces = [[0,1,2],[0,3,1],[1,3,2],[2,3,0]];
+	assert(vnf_add_faces(faces=[for (face=faces) select(verts,face)]) == [verts,faces]);
+}
+test_vnf_add_faces();
+
+
+module test_vnf_merge() {
+	vnf1 = vnf_add_face(pts=[[-1,-1,-1],[1,-1,-1],[0,1,-1]]);
+	vnf2 = vnf_add_face(pts=[[1,1,1],[-1,1,1],[0,1,-1]]);
+	assert(vnf_merge([vnf1,vnf2]) == [[[-1,-1,-1],[1,-1,-1],[0,1,-1],[1,1,1],[-1,1,1],[0,1,-1]],[[0,1,2],[3,4,5]]]);
+}
+test_vnf_merge();
+
+
+module test_vnf_triangulate() {
+	vnf = [[[-1,-1,0],[1,-1,0],[1,1,0],[-1,1,0]],[[0,1,2,3]]];
+	assert(vnf_triangulate(vnf) == [[[-1,-1,0],[1,-1,0],[1,1,0],[-1,1,0]], [[0,1,2],[2,3,0]]]);
+}
+test_vnf_triangulate();
+
+
+module test_vnf_vertex_array() {
+	vnf1 = vnf_vertex_array(
+		points=[for (h=[0:100:100]) [[100,-50,h],[-100,-50,h],[0,100,h]]],
+		col_wrap=true, caps=true
+	);
+	vnf2 = vnf_vertex_array(
+		points=[for (h=[0:100:100]) [[100,-50,h],[-100,-50,h],[0,100,h]]],
+		col_wrap=true, caps=true, style="alt"
+	);
+	vnf3 = vnf_vertex_array(
+		points=[for (h=[0:100:100]) [[100,-50,h],[-100,-50,h],[0,100,h]]],
+		col_wrap=true, caps=true, style="quincunx"
+	);
+	assert(vnf1 == [[[100,-50,0],[-100,-50,0],[0,100,0],[100,-50,100],[-100,-50,100],[0,100,100]],[[0,4,3],[0,1,4],[1,5,4],[1,2,5],[2,3,5],[2,0,3],[2,1,0],[3,4,5]]]);
+	assert(vnf2 == [[[100,-50,0],[-100,-50,0],[0,100,0],[100,-50,100],[-100,-50,100],[0,100,100]],[[0,1,3],[3,1,4],[1,2,4],[4,2,5],[2,0,5],[5,0,3],[2,1,0],[3,4,5]]]);
+	assert(vnf3 == [[[100,-50,0],[-100,-50,0],[0,100,0],[100,-50,100],[-100,-50,100],[0,100,100],[0,-50,50],[-50,25,50],[50,25,50]],[[0,6,3],[3,6,4],[4,6,1],[1,6,0],[1,7,4],[4,7,5],[5,7,2],[2,7,1],[2,8,5],[5,8,3],[3,8,0],[0,8,2],[2,1,0],[3,4,5]]]);
+}
+test_vnf_vertex_array();
+
+
+// vim: noexpandtab tabstop=4 shiftwidth=4 softtabstop=4 nowrap
diff --git a/version.scad b/version.scad
index e5a5486..8af989f 100644
--- a/version.scad
+++ b/version.scad
@@ -8,7 +8,7 @@
 //////////////////////////////////////////////////////////////////////
 
 
-BOSL_VERSION = [2,0,8];
+BOSL_VERSION = [2,0,9];
 
 
 // Section: BOSL Library Version Functions
diff --git a/vnf.scad b/vnf.scad
index db9f7c2..4e59d28 100644
--- a/vnf.scad
+++ b/vnf.scad
@@ -58,6 +58,8 @@ function vnf_faces(vnf) = vnf[1];
 //   vnf4 = vnf_get_vertex(vnf3, p=[[1,3,2],[3,2,1]]);  // Returns: [[1,2], [[[3,5,8],[3,2,1],[1,3,2]],[]]]
 function vnf_get_vertex(vnf=[[],[]], p) =
 	is_path(p)? _vnf_get_vertices(vnf, p) :
+	assert(is_vnf(vnf))
+	assert(is_vector(p))
 	let(
 		p = quant(p,1/1024),  // OpenSCAD internally quantizes objects to 1/1024.
 		v = search([p], vnf[0])[0]
@@ -89,6 +91,8 @@ function _vnf_get_vertices(vnf=[[],[]], pts, _i=0, _idxs=[]) =
 //   vnf = The VNF structure to add a face to.
 //   pts = The vertex points for the face.
 function vnf_add_face(vnf=[[],[]], pts) =
+	assert(is_vnf(vnf))
+	assert(is_path(pts))
 	let(
 		vvnf = vnf_get_vertex(vnf, pts),
 		face = deduplicate(vvnf[0], closed=true),
@@ -111,7 +115,8 @@ function vnf_add_face(vnf=[[],[]], pts) =
 //   vnf = The VNF structure to add a face to.
 //   faces = The list of faces, where each face is given as a list of vertex points.
 function vnf_add_faces(vnf=[[],[]], faces, _i=0) =
-	_i<len(faces)? vnf_add_faces(vnf_add_face(vnf, faces[_i]), faces, _i=_i+1) : vnf;
+	(assert(is_vnf(vnf)) assert(is_list(faces)) _i>=len(faces))? vnf :
+	vnf_add_faces(vnf_add_face(vnf, faces[_i]), faces, _i=_i+1);
 
 
 // Function: vnf_merge()
@@ -119,7 +124,8 @@ function vnf_add_faces(vnf=[[],[]], faces, _i=0) =
 //   vnf = vnf_merge([VNF, VNF, VNF, ...]);
 // Description:
 //   Given a list of VNF structures, merges them all into a single VNF structure.
-function vnf_merge(vnfs=[],_i=0,_acc=[[],[]]) = _i>=len(vnfs)? _acc :
+function vnf_merge(vnfs=[],_i=0,_acc=[[],[]]) =
+	(assert(is_vnf_list(vnfs)) _i>=len(vnfs))? _acc :
 	vnf_merge(
 		vnfs, _i=_i+1,
 		_acc = let(base=len(_acc[0])) [
@@ -225,6 +231,7 @@ function vnf_vertex_array(
 	assert(in_list(style,["default","alt","quincunx"]))
 	let(
 		pts = flatten(points),
+		pcnt = len(pts),
 		rows = len(points),
 		cols = len(points[0]),
 		errchk = [for (row=points) assert(len(row)==cols, "All rows much have the same number of columns.") 0],