diff --git a/src/activation/leaky_relu.rs b/src/activation/leaky_relu.rs
index d6eb274..34915c8 100644
--- a/src/activation/leaky_relu.rs
+++ b/src/activation/leaky_relu.rs
@@ -1,25 +1,9 @@
 /// Returns the result of the leaky rectified linear unit function.
-///
-/// # Examples
-///
-/// ```
-/// # use engram::*;
-/// assert_eq!(leaky_relu(0.0), 0.0, "leaky_relu(0.0)");
-/// assert_eq!(leaky_relu(-10.0), -0.1, "leaky_relu(-10.0)");
-/// ```
 pub fn leaky_relu(x: f64) -> f64 {
     f64::max(x, 0.01 * x)
 }
 
 /// Returns the derivative of the leaky rectified linear unit function.
-///
-/// # Examples
-///
-/// ```
-/// # use engram::*;
-/// assert_eq!(d_leaky_relu(0.0), 0.01, "d_leaky_relu(0.0)");
-/// assert_eq!(d_leaky_relu(-10.0), 0.01, "d_leaky_relu(-10.0)");
-/// ```
 pub fn d_leaky_relu(x: f64) -> f64 {
     if x > 0.0 {
         1.0
@@ -27,3 +11,20 @@ pub fn d_leaky_relu(x: f64) -> f64 {
         0.01
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_leaky_relu() {
+        assert_eq!(leaky_relu(0.0), 0.0, "leaky_relu(0.0)");
+        assert_eq!(leaky_relu(-10.0), -0.1, "leaky_relu(-10.0)");
+    }
+
+    #[test]
+    fn test_d_leaky_relu() {
+        assert_eq!(d_leaky_relu(0.0), 0.01, "d_leaky_relu(0.0)");
+        assert_eq!(d_leaky_relu(-10.0), 0.01, "d_leaky_relu(-10.0)");
+    }
+}
diff --git a/src/activation/relu.rs b/src/activation/relu.rs
index eac215b..f42925a 100644
--- a/src/activation/relu.rs
+++ b/src/activation/relu.rs
@@ -1,25 +1,9 @@
 /// Returns the result of the rectified linear unit function.
-///
-/// # Examples
-///
-/// ```
-/// # use engram::*;
-/// assert_eq!(relu(0.0), 0.0, "relu(0.0)");
-/// assert_eq!(relu(10.0), 10.0, "relu(10.0)");
-/// ```
 pub fn relu(x: f64) -> f64 {
     f64::max(x, 0.0)
 }
 
 /// Returns the derivative of the rectified linear unit function.
-///
-/// # Examples
-///
-/// ```
-/// # use engram::*;
-/// assert_eq!(d_relu(0.0), 0.0, "d_relu(0.0)");
-/// assert_eq!(d_relu(-10.0), 0.0, "d_relu(-10.0)");
-/// ```
 pub fn d_relu(x: f64) -> f64 {
     if x > 0.0 {
         1.0
@@ -27,3 +11,20 @@ pub fn d_relu(x: f64) -> f64 {
         0.0
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_relu() {
+        assert_eq!(relu(0.0), 0.0, "relu(0.0)");
+        assert_eq!(relu(10.0), 10.0, "relu(10.0)");
+    }
+
+    #[test]
+    fn test_d_relu() {
+        assert_eq!(d_relu(0.0), 0.0, "d_relu(0.0)");
+        assert_eq!(d_relu(-10.0), 0.0, "d_relu(-10.0)");
+    }
+}
diff --git a/src/activation/sigmoid.rs b/src/activation/sigmoid.rs
index d067570..61e2479 100644
--- a/src/activation/sigmoid.rs
+++ b/src/activation/sigmoid.rs
@@ -1,26 +1,27 @@
 /// Returns the result of the sigmoid function.
-///
-/// # Examples
-///
-/// ```
-/// # use engram::*;
-/// assert_eq!(sigmoid(0.0), 0.5, "sigmoid(0.0)");
-/// assert_eq!(sigmoid(1.0), 0.7310585786300049, "sigmoid(1.0)");
-/// ```
 pub fn sigmoid(x: f64) -> f64 {
     1.0 / (1.0 + (-x).exp())
 }
 
 /// Returns the derivative of the sigmoid function.
-///
-/// # Examples
-///
-/// ```
-/// # use engram::*;
-/// assert_eq!(d_sigmoid(0.0), 0.25, "d_sigmoid(0.0)");
-/// assert_eq!(d_sigmoid(1.0), 0.19661193324148185, "d_sigmoid(1.0)");
-/// ```
 pub fn d_sigmoid(x: f64) -> f64 {
     let y = sigmoid(x);
     y * (1.0 - y)
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_sigmoid() {
+        assert_eq!(sigmoid(0.0), 0.5, "sigmoid(0.0)");
+        assert_eq!(sigmoid(1.0), 0.7310585786300049, "sigmoid(1.0)");
+    }
+
+    #[test]
+    fn test_d_sigmoid() {
+        assert_eq!(d_sigmoid(0.0), 0.25, "d_sigmoid(0.0)");
+        assert_eq!(d_sigmoid(1.0), 0.19661193324148185, "d_sigmoid(1.0)");
+    }
+}
diff --git a/src/activation/tanh.rs b/src/activation/tanh.rs
index 4d398ec..df3a8b8 100644
--- a/src/activation/tanh.rs
+++ b/src/activation/tanh.rs
@@ -1,25 +1,26 @@
 /// Returns the result of the hyperbolic tangent function.
-///
-/// # Examples
-///
-/// ```
-/// # use engram::*;
-/// assert_eq!(tanh(0.0), 0.0, "tanh(0.0)");
-/// assert_eq!(tanh(1.0), 0.7615941559557649, "tanh(1.0)");
-/// ```
 pub fn tanh(x: f64) -> f64 {
     x.tanh()
 }
 
 /// Returns the derivative of the hyperbolic tangent function.
-///
-/// # Examples
-///
-/// ```
-/// # use engram::*;
-/// assert_eq!(d_tanh(0.0), 1.0, "d_tanh(0.0)");
-/// assert_eq!(d_tanh(1.0), 0.41997434161402614, "d_tanh(1.0)");
-/// ```
 pub fn d_tanh(x: f64) -> f64 {
     1.0 - tanh(x).powi(2)
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_tanh() {
+        assert_eq!(tanh(0.0), 0.0, "tanh(0.0)");
+        assert_eq!(tanh(1.0), 0.7615941559557649, "tanh(1.0)");
+    }
+
+    #[test]
+    fn test_d_tanh() {
+        assert_eq!(d_tanh(0.0), 1.0, "d_tanh(0.0)");
+        assert_eq!(d_tanh(1.0), 0.41997434161402614, "d_tanh(1.0)");
+    }
+}