diff --git a/src/executors/mod.rs b/src/executors/mod.rs
index 98cdc990af..e9682040a6 100644
--- a/src/executors/mod.rs
+++ b/src/executors/mod.rs
@@ -81,3 +81,46 @@ impl Executor for InMemoryExecutor {
         self.base.observers.push(observer);
     }
 }
+
+impl InMemoryExecutor {
+    fn new(harness_fn: HarnessFunction) -> InMemoryExecutor {
+        InMemoryExecutor {
+            base: ExecutorBase {
+                observers: vec![],
+                cur_input: Option::None,
+            },
+            harness: harness_fn,
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::executors::{Executor, ExitKind, InMemoryExecutor};
+    use crate::observers::Observer;
+    use crate::AflError;
+
+    struct Nopserver {}
+
+    impl Observer for Nopserver {
+        fn reset(&mut self) -> Result<(), AflError> {
+            Err(AflError::Unknown)
+        }
+        fn post_exec(&mut self) -> Result<(), AflError> {
+            Err(AflError::Unknown)
+        }
+    }
+
+    fn test_harness_fn_nop(_executor: &dyn Executor, buf: &[u8]) -> ExitKind {
+        println! {"Fake exec with buf of len {}", buf.len()};
+        ExitKind::Ok
+    }
+
+    #[test]
+    fn test_inmem_post_exec() {
+        let mut in_mem_executor = InMemoryExecutor::new(test_harness_fn_nop);
+        let nopserver = Nopserver {};
+        in_mem_executor.add_observer(Box::new(nopserver));
+        assert_eq!(in_mem_executor.post_exec_observers().is_err(), true);
+    }
+}
diff --git a/src/inputs/bytes.rs b/src/inputs/bytes.rs
index e2ad2cbd90..5b226c1061 100644
--- a/src/inputs/bytes.rs
+++ b/src/inputs/bytes.rs
@@ -16,3 +16,27 @@ impl Input for BytesInput {
         Ok(())
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use crate::utils::{next_pow2, Rand, Xoshiro256StarRand};
+
+    #[test]
+    fn test_input() {
+        let mut rand = Xoshiro256StarRand::new();
+        assert_ne!(rand.next(), rand.next());
+        assert!(rand.below(100) < 100);
+        assert_eq!(rand.below(1), 0);
+        assert_eq!(rand.between(10, 10), 10);
+        assert!(rand.between(11, 20) > 10);
+    }
+
+    #[test]
+    fn test_next_pow2() {
+        assert_eq!(next_pow2(0), 0);
+        assert_eq!(next_pow2(1), 1);
+        assert_eq!(next_pow2(2), 2);
+        assert_eq!(next_pow2(3), 4);
+        assert_eq!(next_pow2(1000), 1024);
+    }
+}
diff --git a/src/utils.rs b/src/utils.rs
index 7b87525cbd..11cd541189 100644
--- a/src/utils.rs
+++ b/src/utils.rs
@@ -88,7 +88,7 @@ impl Xoshiro256StarRand {
 }
 
 /// Get the next higher power of two
-fn next_pow2(val: u64) -> u64 {
+pub fn next_pow2(val: u64) -> u64 {
     // Early exit so we don't have to do a wrapping subtract;
     if val <= 2 {
         return val;