diff --git a/src/code.rs b/src/code.rs
index 1c72952..9c507af 100644
--- a/src/code.rs
+++ b/src/code.rs
@@ -198,3 +198,18 @@ pub fn program2gcode<W: Write>(p: &Program, mut w: W) -> io::Result<()> {
     }
     Ok(())
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_validate_gcode() {
+        panic!("TODO: basic passing test");
+    }
+
+    #[test]
+    fn test_program2gcode() {
+        panic!("TODO: basic passing test");
+    }
+}
diff --git a/src/machine.rs b/src/machine.rs
index b6e1c6c..3ecda79 100644
--- a/src/machine.rs
+++ b/src/machine.rs
@@ -1,6 +1,4 @@
-/// State machine used to generate gcode for various operations.
-///
-/// TODO: more detailed examples
+/// TODO: Documentation
 
 use crate::code::*;
 
@@ -92,3 +90,33 @@ impl Machine {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_tool_on() {
+        panic!("TODO: basic passing test");
+    }
+
+    #[test]
+    fn test_tool_off() {
+        panic!("TODO: basic passing test");
+    }
+
+    #[test]
+    fn test_distance() {
+        panic!("TODO: basic passing test");
+    }
+
+    #[test]
+    fn test_absolute() {
+        panic!("TODO: basic passing test");
+    }
+
+    #[test]
+    fn test_incremental() {
+        panic!("TODO: basic passing test");
+    }
+}
diff --git a/src/main.rs b/src/main.rs
index 21e887c..6f0f187 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -313,3 +313,18 @@ fn length_to_mm(l: svgdom::Length, dpi: f64) -> f64 {
 
     length.get::<millimeter>()
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_svg2program() {
+        panic!("TODO: basic passing test");
+    }
+
+    #[test]
+    fn test_length_to_mm() {
+        panic!("TODO: basic passing test");
+    }
+}
diff --git a/src/turtle.rs b/src/turtle.rs
index cc97954..5f75c97 100644
--- a/src/turtle.rs
+++ b/src/turtle.rs
@@ -185,6 +185,7 @@ impl Turtle {
     }
 
     // TODO: Documentation
+    // TODO: Function too long
     pub fn cubic_bezier<Z, F>(
         &mut self,
         abs: bool,
@@ -430,3 +431,73 @@ impl Turtle {
         self.initpos = self.curpos;
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_move_to() {
+        panic!("TODO: basic passing test");
+    }
+
+    #[test]
+    fn test_close() {
+        panic!("TODO: basic passing test");
+    }
+
+    #[test]
+    fn test_line() {
+        panic!("TODO: basic passing test");
+    }
+
+    #[test]
+    fn test_bezier() {
+        panic!("TODO: basic passing test");
+    }
+
+    #[test]
+    fn test_cubic_bezier() {
+        panic!("TODO: basic passing test");
+    }
+
+    #[test]
+    fn test_smooth_cubic_bezier() {
+        panic!("TODO: basic passing test");
+    }
+
+    #[test]
+    fn test_smooth_quadratic_bezier() {
+        panic!("TODO: basic passing test");
+    }
+
+    #[test]
+    fn test_quadratic_bezier() {
+        panic!("TODO: basic passing test");
+    }
+
+    #[test]
+    fn test_elliptical() {
+        panic!("TODO: basic passing test");
+    }
+
+    #[test]
+    fn test_stack_scaling() {
+        panic!("TODO: basic passing test");
+    }
+
+    #[test]
+    fn test_push_transform() {
+        panic!("TODO: basic passing test");
+    }
+
+    #[test]
+    fn test_pop_transform() {
+        panic!("TODO: basic passing test");
+    }
+
+    #[test]
+    fn test_reset() {
+        panic!("TODO: basic passing test");
+    }
+}