diff --git a/postgres-protocol/src/types.rs b/postgres-protocol/src/types/mod.rs
similarity index 85%
rename from postgres-protocol/src/types.rs
rename to postgres-protocol/src/types/mod.rs
index 7fac2b9d8..46000c407 100644
--- a/postgres-protocol/src/types.rs
+++ b/postgres-protocol/src/types/mod.rs
@@ -7,6 +7,9 @@ use std::str;
 
 use crate::{write_nullable, FromUsize, IsNull, Oid};
 
+#[cfg(test)]
+mod test;
+
 const RANGE_UPPER_UNBOUNDED: u8 = 0b0001_0000;
 const RANGE_LOWER_UNBOUNDED: u8 = 0b0000_1000;
 const RANGE_UPPER_INCLUSIVE: u8 = 0b0000_0100;
@@ -953,163 +956,3 @@ impl<'a> FallibleIterator for PathPoints<'a> {
         (len, Some(len))
     }
 }
-
-#[cfg(test)]
-mod test {
-    use fallible_iterator::FallibleIterator;
-    use std::collections::HashMap;
-
-    use super::*;
-    use crate::IsNull;
-
-    #[test]
-    fn bool() {
-        let mut buf = vec![];
-        bool_to_sql(true, &mut buf);
-        assert_eq!(bool_from_sql(&buf).unwrap(), true);
-
-        let mut buf = vec![];
-        bool_to_sql(false, &mut buf);
-        assert_eq!(bool_from_sql(&buf).unwrap(), false);
-    }
-
-    #[test]
-    fn int2() {
-        let mut buf = vec![];
-        int2_to_sql(0x0102, &mut buf);
-        assert_eq!(int2_from_sql(&buf).unwrap(), 0x0102);
-    }
-
-    #[test]
-    fn int4() {
-        let mut buf = vec![];
-        int4_to_sql(0x0102_0304, &mut buf);
-        assert_eq!(int4_from_sql(&buf).unwrap(), 0x0102_0304);
-    }
-
-    #[test]
-    fn int8() {
-        let mut buf = vec![];
-        int8_to_sql(0x0102_0304_0506_0708, &mut buf);
-        assert_eq!(int8_from_sql(&buf).unwrap(), 0x0102_0304_0506_0708);
-    }
-
-    #[test]
-    #[allow(clippy::float_cmp)]
-    fn float4() {
-        let mut buf = vec![];
-        float4_to_sql(10343.95, &mut buf);
-        assert_eq!(float4_from_sql(&buf).unwrap(), 10343.95);
-    }
-
-    #[test]
-    #[allow(clippy::float_cmp)]
-    fn float8() {
-        let mut buf = vec![];
-        float8_to_sql(10343.95, &mut buf);
-        assert_eq!(float8_from_sql(&buf).unwrap(), 10343.95);
-    }
-
-    #[test]
-    fn hstore() {
-        let mut map = HashMap::new();
-        map.insert("hello", Some("world"));
-        map.insert("hola", None);
-
-        let mut buf = vec![];
-        hstore_to_sql(map.iter().map(|(&k, &v)| (k, v)), &mut buf).unwrap();
-        assert_eq!(
-            hstore_from_sql(&buf)
-                .unwrap()
-                .collect::<HashMap<_, _>>()
-                .unwrap(),
-            map
-        );
-    }
-
-    #[test]
-    fn varbit() {
-        let len = 12;
-        let bits = [0b0010_1011, 0b0000_1111];
-
-        let mut buf = vec![];
-        varbit_to_sql(len, bits.iter().cloned(), &mut buf).unwrap();
-        let out = varbit_from_sql(&buf).unwrap();
-        assert_eq!(out.len(), len);
-        assert_eq!(out.bytes(), bits);
-    }
-
-    #[test]
-    fn array() {
-        let dimensions = [
-            ArrayDimension {
-                len: 1,
-                lower_bound: 10,
-            },
-            ArrayDimension {
-                len: 2,
-                lower_bound: 0,
-            },
-        ];
-        let values = [None, Some(&b"hello"[..])];
-
-        let mut buf = vec![];
-        array_to_sql(
-            dimensions.iter().cloned(),
-            10,
-            values.iter().cloned(),
-            |v, buf| match v {
-                Some(v) => {
-                    buf.extend_from_slice(v);
-                    Ok(IsNull::No)
-                }
-                None => Ok(IsNull::Yes),
-            },
-            &mut buf,
-        )
-        .unwrap();
-
-        let array = array_from_sql(&buf).unwrap();
-        assert_eq!(array.has_nulls(), true);
-        assert_eq!(array.element_type(), 10);
-        assert_eq!(array.dimensions().collect::<Vec<_>>().unwrap(), dimensions);
-        assert_eq!(array.values().collect::<Vec<_>>().unwrap(), values);
-    }
-
-    #[test]
-    fn non_null_array() {
-        let dimensions = [
-            ArrayDimension {
-                len: 1,
-                lower_bound: 10,
-            },
-            ArrayDimension {
-                len: 2,
-                lower_bound: 0,
-            },
-        ];
-        let values = [Some(&b"hola"[..]), Some(&b"hello"[..])];
-
-        let mut buf = vec![];
-        array_to_sql(
-            dimensions.iter().cloned(),
-            10,
-            values.iter().cloned(),
-            |v, buf| match v {
-                Some(v) => {
-                    buf.extend_from_slice(v);
-                    Ok(IsNull::No)
-                }
-                None => Ok(IsNull::Yes),
-            },
-            &mut buf,
-        )
-        .unwrap();
-
-        let array = array_from_sql(&buf).unwrap();
-        assert_eq!(array.has_nulls(), false);
-        assert_eq!(array.element_type(), 10);
-        assert_eq!(array.dimensions().collect::<Vec<_>>().unwrap(), dimensions);
-        assert_eq!(array.values().collect::<Vec<_>>().unwrap(), values);
-    }
-}
diff --git a/postgres-protocol/src/types/test.rs b/postgres-protocol/src/types/test.rs
new file mode 100644
index 000000000..7d2563555
--- /dev/null
+++ b/postgres-protocol/src/types/test.rs
@@ -0,0 +1,156 @@
+use fallible_iterator::FallibleIterator;
+use std::collections::HashMap;
+
+use super::*;
+use crate::IsNull;
+
+#[test]
+fn bool() {
+    let mut buf = vec![];
+    bool_to_sql(true, &mut buf);
+    assert_eq!(bool_from_sql(&buf).unwrap(), true);
+
+    let mut buf = vec![];
+    bool_to_sql(false, &mut buf);
+    assert_eq!(bool_from_sql(&buf).unwrap(), false);
+}
+
+#[test]
+fn int2() {
+    let mut buf = vec![];
+    int2_to_sql(0x0102, &mut buf);
+    assert_eq!(int2_from_sql(&buf).unwrap(), 0x0102);
+}
+
+#[test]
+fn int4() {
+    let mut buf = vec![];
+    int4_to_sql(0x0102_0304, &mut buf);
+    assert_eq!(int4_from_sql(&buf).unwrap(), 0x0102_0304);
+}
+
+#[test]
+fn int8() {
+    let mut buf = vec![];
+    int8_to_sql(0x0102_0304_0506_0708, &mut buf);
+    assert_eq!(int8_from_sql(&buf).unwrap(), 0x0102_0304_0506_0708);
+}
+
+#[test]
+#[allow(clippy::float_cmp)]
+fn float4() {
+    let mut buf = vec![];
+    float4_to_sql(10343.95, &mut buf);
+    assert_eq!(float4_from_sql(&buf).unwrap(), 10343.95);
+}
+
+#[test]
+#[allow(clippy::float_cmp)]
+fn float8() {
+    let mut buf = vec![];
+    float8_to_sql(10343.95, &mut buf);
+    assert_eq!(float8_from_sql(&buf).unwrap(), 10343.95);
+}
+
+#[test]
+fn hstore() {
+    let mut map = HashMap::new();
+    map.insert("hello", Some("world"));
+    map.insert("hola", None);
+
+    let mut buf = vec![];
+    hstore_to_sql(map.iter().map(|(&k, &v)| (k, v)), &mut buf).unwrap();
+    assert_eq!(
+        hstore_from_sql(&buf)
+            .unwrap()
+            .collect::<HashMap<_, _>>()
+            .unwrap(),
+        map
+    );
+}
+
+#[test]
+fn varbit() {
+    let len = 12;
+    let bits = [0b0010_1011, 0b0000_1111];
+
+    let mut buf = vec![];
+    varbit_to_sql(len, bits.iter().cloned(), &mut buf).unwrap();
+    let out = varbit_from_sql(&buf).unwrap();
+    assert_eq!(out.len(), len);
+    assert_eq!(out.bytes(), bits);
+}
+
+#[test]
+fn array() {
+    let dimensions = [
+        ArrayDimension {
+            len: 1,
+            lower_bound: 10,
+        },
+        ArrayDimension {
+            len: 2,
+            lower_bound: 0,
+        },
+    ];
+    let values = [None, Some(&b"hello"[..])];
+
+    let mut buf = vec![];
+    array_to_sql(
+        dimensions.iter().cloned(),
+        10,
+        values.iter().cloned(),
+        |v, buf| match v {
+            Some(v) => {
+                buf.extend_from_slice(v);
+                Ok(IsNull::No)
+            }
+            None => Ok(IsNull::Yes),
+        },
+        &mut buf,
+    )
+    .unwrap();
+
+    let array = array_from_sql(&buf).unwrap();
+    assert_eq!(array.has_nulls(), true);
+    assert_eq!(array.element_type(), 10);
+    assert_eq!(array.dimensions().collect::<Vec<_>>().unwrap(), dimensions);
+    assert_eq!(array.values().collect::<Vec<_>>().unwrap(), values);
+}
+
+#[test]
+fn non_null_array() {
+    let dimensions = [
+        ArrayDimension {
+            len: 1,
+            lower_bound: 10,
+        },
+        ArrayDimension {
+            len: 2,
+            lower_bound: 0,
+        },
+    ];
+    let values = [Some(&b"hola"[..]), Some(&b"hello"[..])];
+
+    let mut buf = vec![];
+    array_to_sql(
+        dimensions.iter().cloned(),
+        10,
+        values.iter().cloned(),
+        |v, buf| match v {
+            Some(v) => {
+                buf.extend_from_slice(v);
+                Ok(IsNull::No)
+            }
+            None => Ok(IsNull::Yes),
+        },
+        &mut buf,
+    )
+    .unwrap();
+
+    let array = array_from_sql(&buf).unwrap();
+    assert_eq!(array.has_nulls(), false);
+    assert_eq!(array.element_type(), 10);
+    assert_eq!(array.dimensions().collect::<Vec<_>>().unwrap(), dimensions);
+    assert_eq!(array.values().collect::<Vec<_>>().unwrap(), values);
+}