diff --git a/README.md b/README.md
index a310d69..c19bfb0 100644
--- a/README.md
+++ b/README.md
@@ -20,6 +20,20 @@ Commands:
 @grahamcofborg build list of attrs
 ```
 
+This will run `nix-build ./default.nix -A list -A of -A attrs` in
+the nixpkgs checkout.
+
+---
+
+```
+@grahamcofborg test list of tests
+```
+
+This will run `nix-build ./nixos/default.nix -A tests.list -A tests.of -A tests.attrs` in
+the nixpkgs checkout. Note: this will only run on x86_64-linux machines.
+
+---
+
 ```
 @grahamcofborg eval
 ```
diff --git a/ofborg/src/commentparser.rs b/ofborg/src/commentparser.rs
index 3eec94e..9a5effe 100644
--- a/ofborg/src/commentparser.rs
+++ b/ofborg/src/commentparser.rs
@@ -23,6 +23,17 @@ pub fn parse(text: &str) -> Option<Vec<Instruction>> {
             "build" => {
                 instructions.push(Instruction::Build(Subset::Nixpkgs, right.to_vec()))
             }
+            "test" => {
+                instructions.push(
+                    Instruction::Build(Subset::NixOS,
+                                       right
+                                       .into_iter()
+                                       .map(|attr| format!("tests.{}", attr))
+                                       .collect()
+                    )
+                );
+
+            }
             "eval" => {
                 instructions.push(Instruction::Eval)
             }
@@ -119,6 +130,16 @@ mod tests {
 baz"));
     }
 
+    #[test]
+    fn test_comment() {
+        assert_eq!(Some(vec![Instruction::Build(Subset::NixOS, vec![
+            String::from("tests.foo"),
+            String::from("tests.bar"),
+            String::from("tests.baz")
+        ])]),
+                   parse("@GrahamCOfBorg test foo bar baz"));
+    }
+
     #[test]
     fn build_comment_newlines() {
         assert_eq!(Some(vec![Instruction::Build(Subset::Nixpkgs, vec![