diff --git a/src/io.js b/src/io.js
index 70b0946..73a6943 100644
--- a/src/io.js
+++ b/src/io.js
@@ -69,7 +69,7 @@ exports.threedee = async (script, debug) => {
         })
     })
     const result = {
-        stl: jscad.generateOutput('stla', compiled).asBuffer()
+        stl: jscad.generateOutput('stla', compiled).asBuffer().toString()
     }
     if (debug) {
         result.jscad = script
diff --git a/test/cases/001_cube.yaml b/test/cases/001_cube.yaml
new file mode 100644
index 0000000..ff8aaa5
--- /dev/null
+++ b/test/cases/001_cube.yaml
@@ -0,0 +1,16 @@
+points:
+    zones:
+        arst:
+            columns:
+                c1:
+                    rows:
+                        r1:
+outlines:
+    exports:
+        square:
+            - type: rectangle
+              size: [5, 5]
+cases:
+    cube:
+        - name: square
+          extrude: 5
\ No newline at end of file
diff --git a/test/cases/001_cube___cases_cube_stl.stl b/test/cases/001_cube___cases_cube_stl.stl
new file mode 100644
index 0000000..038a3bc
--- /dev/null
+++ b/test/cases/001_cube___cases_cube_stl.stl
@@ -0,0 +1,86 @@
+solid csg.js
+facet normal 0 0 -1
+outer loop
+vertex 0 5 0
+vertex 5 5 0
+vertex 5 0 0
+endloop
+endfacet
+facet normal 0 0 -1
+outer loop
+vertex 0 5 0
+vertex 5 0 0
+vertex 0 0 0
+endloop
+endfacet
+facet normal 0 0 1
+outer loop
+vertex 0 5 5
+vertex 0 0 5
+vertex 5 0 5
+endloop
+endfacet
+facet normal 0 0 1
+outer loop
+vertex 0 5 5
+vertex 5 0 5
+vertex 5 5 5
+endloop
+endfacet
+facet normal 0 -1 0
+outer loop
+vertex 5 0 0
+vertex 5 0 5
+vertex 0 0 5
+endloop
+endfacet
+facet normal 0 -1 0
+outer loop
+vertex 5 0 0
+vertex 0 0 5
+vertex 0 0 0
+endloop
+endfacet
+facet normal 1 0 0
+outer loop
+vertex 5 5 0
+vertex 5 5 5
+vertex 5 0 5
+endloop
+endfacet
+facet normal 1 0 0
+outer loop
+vertex 5 5 0
+vertex 5 0 5
+vertex 5 0 0
+endloop
+endfacet
+facet normal 0 1 0
+outer loop
+vertex 5 5 5
+vertex 5 5 0
+vertex 0 5 0
+endloop
+endfacet
+facet normal 0 1 0
+outer loop
+vertex 5 5 5
+vertex 0 5 0
+vertex 0 5 5
+endloop
+endfacet
+facet normal -1 0 0
+outer loop
+vertex 0 5 5
+vertex 0 5 0
+vertex 0 0 0
+endloop
+endfacet
+facet normal -1 0 0
+outer loop
+vertex 0 5 5
+vertex 0 0 0
+vertex 0 0 5
+endloop
+endfacet
+endsolid csg.js