diff --git a/crates/test/src/lib.rs b/crates/test/src/lib.rs
index 8b036111a3..2ff31211c1 100644
--- a/crates/test/src/lib.rs
+++ b/crates/test/src/lib.rs
@@ -90,3 +90,38 @@ mod test {
         assert_eq!(h.buffer.as_mut_ptr() as usize % 4096, 0);
     }
 }
+
+use wiggle_runtime::GuestError;
+
+pub struct WasiCtx {
+    pub guest_errors: Vec<GuestError>,
+}
+
+impl WasiCtx {
+    pub fn new() -> Self {
+        Self {
+            guest_errors: vec![],
+        }
+    }
+}
+
+// Errno is used as a first return value in the functions above, therefore
+// it must implement GuestErrorType with type Context = WasiCtx.
+// The context type should let you do logging or debugging or whatever you need
+// with these errors. We just push them to vecs.
+#[macro_export]
+macro_rules! impl_errno {
+    ( $errno:ty ) => {
+        impl wiggle_runtime::GuestErrorType for $errno {
+            type Context = WasiCtx;
+            fn success() -> $errno {
+                <$errno>::Ok
+            }
+            fn from_error(e: GuestError, ctx: &mut WasiCtx) -> $errno {
+                eprintln!("GUEST ERROR: {:?}", e);
+                ctx.guest_errors.push(e);
+                types::Errno::InvalidArg
+            }
+        }
+    };
+}
diff --git a/tests/ctx.rs b/tests/ctx.rs
deleted file mode 100644
index b521dbaa40..0000000000
--- a/tests/ctx.rs
+++ /dev/null
@@ -1,34 +0,0 @@
-use wiggle_runtime::GuestError;
-
-pub struct WasiCtx {
-    pub guest_errors: Vec<GuestError>,
-}
-
-impl WasiCtx {
-    pub fn new() -> Self {
-        Self {
-            guest_errors: vec![],
-        }
-    }
-}
-
-// Errno is used as a first return value in the functions above, therefore
-// it must implement GuestErrorType with type Context = WasiCtx.
-// The context type should let you do logging or debugging or whatever you need
-// with these errors. We just push them to vecs.
-#[macro_export]
-macro_rules! impl_errno {
-    ( $errno:ty ) => {
-        impl wiggle_runtime::GuestErrorType for $errno {
-            type Context = WasiCtx;
-            fn success() -> $errno {
-                <$errno>::Ok
-            }
-            fn from_error(e: GuestError, ctx: &mut WasiCtx) -> $errno {
-                eprintln!("GUEST ERROR: {:?}", e);
-                ctx.guest_errors.push(e);
-                types::Errno::InvalidArg
-            }
-        }
-    };
-}
diff --git a/tests/main.rs b/tests/main.rs
index a8ec2c5096..43254739fb 100644
--- a/tests/main.rs
+++ b/tests/main.rs
@@ -3,16 +3,13 @@ use std::convert::TryFrom;
 use wiggle_runtime::{
     GuestArray, GuestError, GuestPtr, GuestPtrMut, GuestRef, GuestRefMut, GuestString,
 };
-use wiggle_test::{HostMemory, MemArea};
+use wiggle_test::{impl_errno, HostMemory, MemArea, WasiCtx};
 
 wiggle_generate::from_witx!({
     witx: ["tests/test.witx"],
     ctx: WasiCtx,
 });
 
-mod ctx;
-use ctx::WasiCtx;
-
 impl_errno!(types::Errno);
 
 impl foo::Foo for WasiCtx {
diff --git a/tests/trivial.rs b/tests/trivial.rs
index 36ca5d3ca5..de97dd8a05 100644
--- a/tests/trivial.rs
+++ b/tests/trivial.rs
@@ -1,9 +1,6 @@
 use proptest::prelude::*;
 use wiggle_runtime::GuestError;
-use wiggle_test::HostMemory;
-
-mod ctx;
-use ctx::WasiCtx;
+use wiggle_test::{impl_errno, HostMemory, WasiCtx};
 
 wiggle_generate::from_witx!({
     witx: ["tests/trivial.witx"],