diff --git a/.travis.yml b/.travis.yml
index 023da4ce..322a51b4 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,14 +4,14 @@ branches:
 
 os:
   - linux
-  - osx
+  # - osx
 
 language: rust
 
 rust:
   - stable
-  - beta
-  - nightly
+  # - beta
+  # - nightly
 
   # the earliest supported stable release; we depend upon
   #  * >= 1.32 for uniform module paths
@@ -38,7 +38,7 @@ env:
     - RUSTFLAGS="-A unknown-lints -D warnings"
   matrix:
     - CARGOFLAGS=""
-    - CARGOFLAGS="--release"
+    # - CARGOFLAGS="--release"
 
 before_script:
   - rustup update
@@ -83,28 +83,23 @@ matrix:
     - name: coverage
       rust: stable
       os: linux
-      dist: xenial
-      sudo: required
+      dist: bionic
 
       addons:
         apt:
           packages:
-            - libcurl4-openssl-dev
-            - libdw-dev
-            - libelf-dev
-            - libiberty-dev
             - libsodium-dev
-            - binutils-dev
-            - cmake
+            - libssl-dev
 
       env:
         - COVERAGE=true
 
       before_script:
         - rustup update
-        - cargo install cargo-update || echo "cargo-update already installed"
-        - cargo install cargo-travis || echo "cargo-travis already installed"
+        - cargo install cargo-update    || echo "cargo-update already installed"
+        - cargo install cargo-tarpaulin || echo "cargo-tarpaulin already installed"
         - cargo install-update -a
 
       script:
-        - cargo coveralls --exclude-pattern "_ctest.rs,_ctest.c"
+        - cargo build
+        - cargo tarpaulin --ciserver travis-ci --coveralls $TRAVIS_JOB_ID --tests --no-fail-fast
diff --git a/src/boxed.rs b/src/boxed.rs
index 843f73ca..25bdb4ba 100644
--- a/src/boxed.rs
+++ b/src/boxed.rs
@@ -483,8 +483,6 @@ fn mprotect<T>(ptr: *const T, prot: Prot) {
     }
 }
 
-// LCOV_EXCL_START
-
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -700,12 +698,14 @@ mod tests {
 #[cfg(test)]
 mod tests_sigsegv {
     use super::*;
-    use std::process;
 
+    #[cfg(not(tarpaulin))]
     fn assert_sigsegv<F>(f: F)
     where
         F: FnOnce(),
     {
+        use std::process;
+
         unsafe {
             let pid      : libc::pid_t = libc::fork();
             let mut stat : libc::c_int = 0;
@@ -733,6 +733,10 @@ mod tests_sigsegv {
         }
     }
 
+    #[cfg(tarpaulin)]
+    fn assert_sigsegv<F>(_f: F) where F: FnOnce() {
+    }
+
     #[test]
     fn it_kills_attempts_to_read_while_locked() {
         assert_sigsegv(|| {
@@ -864,5 +868,3 @@ mod tests_proven_statements {
         let _ = boxed.as_mut_slice();
     }
 }
-
-// LCOV_EXCL_STOP
diff --git a/src/ffi/sodium.rs b/src/ffi/sodium.rs
index 52c53296..40266ff1 100644
--- a/src/ffi/sodium.rs
+++ b/src/ffi/sodium.rs
@@ -210,8 +210,6 @@ pub(crate) fn memrandom(bytes: &mut [u8]) {
     unsafe { randombytes_buf(bytes.as_mut_ptr() as *mut _, bytes.len()) }
 }
 
-// LCOV_EXCL_START
-
 #[cfg(test)]
 mod test {
     use super::*;
@@ -236,5 +234,3 @@ mod test {
         assert!(!memcmp(&c, &a));
     }
 }
-
-// LCOV_EXCL_STOP
diff --git a/src/lib.rs b/src/lib.rs
index f849b19d..576ac249 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,5 +1,3 @@
-// LCOV_EXCL_LINE
-
 //! Protected-access memory for cryptographic secrets.
 //!
 //! Provides a convenient way to allocate and access memory for
diff --git a/src/secret.rs b/src/secret.rs
index 05f8b27d..a3d48076 100644
--- a/src/secret.rs
+++ b/src/secret.rs
@@ -246,8 +246,6 @@ impl<T: Bytes> PartialEq for RefMut<'_, T> {
 
 impl<T: Bytes> Eq for RefMut<'_, T> {}
 
-// LCOV_EXCL_START
-
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -358,5 +356,3 @@ mod tests {
         Secret::<u8>::zero(|_| sodium::fail());
     }
 }
-
-// LCOV_EXCL_STOP
diff --git a/src/secret_box.rs b/src/secret_box.rs
index 5ea1b2db..1915f7ac 100644
--- a/src/secret_box.rs
+++ b/src/secret_box.rs
@@ -406,8 +406,6 @@ impl<T: Bytes> PartialEq<Ref<'_, T>> for RefMut<'_, T> {
 
 impl<T: Bytes> Eq for RefMut<'_, T> {}
 
-// LCOV_EXCL_START
-
 #[cfg(test)]
 mod test {
     use super::*;
@@ -558,5 +556,3 @@ mod tests_proven_statements {
         let     _     = boxed.as_mut();
     }
 }
-
-// LCOV_EXCL_STOP
diff --git a/src/secret_vec.rs b/src/secret_vec.rs
index 1ef9d12d..aea16554 100644
--- a/src/secret_vec.rs
+++ b/src/secret_vec.rs
@@ -413,8 +413,6 @@ impl<T: Bytes> PartialEq<Ref<'_, T>> for RefMut<'_, T> {
 
 impl<T: Bytes> Eq for RefMut<'_, T> {}
 
-// LCOV_EXCL_START
-
 #[cfg(test)]
 mod test {
     use super::*;
@@ -550,5 +548,3 @@ mod test {
         assert_eq!(secret_2.borrow_mut(), secret_1.borrow());
     }
 }
-
-// LCOV_EXCL_STOP
diff --git a/src/traits/bytes.rs b/src/traits/bytes.rs
index 3abbd9dd..79102198 100644
--- a/src/traits/bytes.rs
+++ b/src/traits/bytes.rs
@@ -109,3 +109,42 @@ unsafe impl<T: Bytes> AsContiguousBytes for [T] {
         self.as_ptr() as *mut _
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[derive(Copy, Clone)]
+    struct Byte (u8);
+
+    unsafe impl Bytes for Byte {}
+
+    #[test]
+    fn it_uninitializes_to_a_garbage_value() {
+        let b = Byte::uninitialized();
+
+        assert_eq!(b.0, GARBAGE_VALUE);
+    }
+
+    #[test]
+    fn it_reports_size_correctly() {
+        assert_eq!(<Byte as Bytes>::size(), 1);
+    }
+
+    #[test]
+    fn it_provides_ptr_access() {
+        unsafe {
+            let b = Byte(255);
+            assert_eq!(*Bytes::as_u8_ptr(&b), 255);
+        }
+    }
+
+    #[test]
+    fn it_provides_mut_ptr_access() {
+        unsafe {
+            let mut b = Byte(10);
+            *Bytes::as_mut_u8_ptr(&mut b) = 42;
+            assert_eq!(b.0, 42);
+        }
+    }
+}