diff --git a/src/add.go b/src/add.go
new file mode 100644
index 0000000..d70e9b6
--- /dev/null
+++ b/src/add.go
@@ -0,0 +1,6 @@
+package main
+
+// Sophisticated mathematics for sophisticated homosapiens
+func add(x, y int) int {
+	return x + y
+}
diff --git a/src/add_test.go b/src/add_test.go
new file mode 100644
index 0000000..6d71b34
--- /dev/null
+++ b/src/add_test.go
@@ -0,0 +1,16 @@
+package main
+
+import (
+	"testing"
+)
+
+// This file is named add_test.go by convention.
+// The go test command will automatically detect this file and run it.
+// All test files must be named *_test.go and all test functions must be named Test*.
+
+// TestAdd is a test function
+func TestAdd(t *testing.T) {
+	if add(1, 2) != 3 {
+		t.Error("Expected 3")
+	}
+}
diff --git a/src/greet.go b/src/greet.go
index 7da9fa1..baabdf1 100644
--- a/src/greet.go
+++ b/src/greet.go
@@ -1,7 +1,10 @@
 package main
 
-import "fmt"
+import (
+	"fmt"
+)
 
+// Greets the world
 func greet() {
 	fmt.Println("Hello World!")
 }
diff --git a/src/main.go b/src/main.go
index 2cebd34..218ca75 100644
--- a/src/main.go
+++ b/src/main.go
@@ -2,4 +2,5 @@ package main
 
 func main() {
 	greet()
+	println(add(1, 2))
 }