diff --git a/crates/aiken-lang/src/format.rs b/crates/aiken-lang/src/format.rs
index 353aa117..2b8ea754 100644
--- a/crates/aiken-lang/src/format.rs
+++ b/crates/aiken-lang/src/format.rs
@@ -239,6 +239,7 @@ impl<'comments> Formatter<'comments> {
                 return_annotation,
                 body,
                 *end_position,
+                false,
             ),
 
             Definition::Validator(Validator {
@@ -258,12 +259,13 @@ impl<'comments> Formatter<'comments> {
                 ..
             }) => self.definition_fn(
                 &false,
-                if *can_error { "!test" } else { "test" },
+                "test",
                 name,
                 args,
                 &None,
                 body,
                 *end_position,
+                *can_error,
             ),
 
             Definition::TypeAlias(TypeAlias {
@@ -483,13 +485,15 @@ impl<'comments> Formatter<'comments> {
         return_annotation: &'a Option<Annotation>,
         body: &'a UntypedExpr,
         end_location: usize,
+        can_error: bool,
     ) -> Document<'a> {
         // Fn name and args
         let head = pub_(*public)
             .append(keyword)
             .append(" ")
             .append(name)
-            .append(wrap_args(args.iter().map(|e| (self.fn_arg(e), false))));
+            .append(wrap_args(args.iter().map(|e| (self.fn_arg(e), false))))
+            .append(if can_error { " fail" } else { "" });
 
         // Add return annotation
         let head = match return_annotation {
@@ -532,6 +536,7 @@ impl<'comments> Formatter<'comments> {
                 &fun.return_annotation,
                 &fun.body,
                 fun.end_position,
+                false,
             )
             .group();
         let first_fn = commented(fun_doc_comments.append(first_fn).group(), fun_comments);
@@ -551,6 +556,7 @@ impl<'comments> Formatter<'comments> {
                         &other.return_annotation,
                         &other.body,
                         other.end_position,
+                        false,
                     )
                     .group();
 
diff --git a/crates/aiken-lang/src/parser/definition/snapshots/fail.snap b/crates/aiken-lang/src/parser/definition/snapshots/def_test_fail.snap
similarity index 74%
rename from crates/aiken-lang/src/parser/definition/snapshots/fail.snap
rename to crates/aiken-lang/src/parser/definition/snapshots/def_test_fail.snap
index efa48064..a6e3e07b 100644
--- a/crates/aiken-lang/src/parser/definition/snapshots/fail.snap
+++ b/crates/aiken-lang/src/parser/definition/snapshots/def_test_fail.snap
@@ -1,22 +1,22 @@
 ---
 source: crates/aiken-lang/src/parser/definition/test.rs
-description: "Code:\n\n!test invalid_inputs() {\n  expect True = False\n\n  False\n}\n"
+description: "Code:\n\ntest invalid_inputs() fail {\n  expect True = False\n\n  False\n}\n"
 ---
 Test(
     Function {
         arguments: [],
         body: Sequence {
-            location: 27..55,
+            location: 31..59,
             expressions: [
                 Assignment {
-                    location: 27..46,
+                    location: 31..50,
                     value: Var {
-                        location: 41..46,
+                        location: 45..50,
                         name: "False",
                     },
                     pattern: Constructor {
                         is_record: false,
-                        location: 34..38,
+                        location: 38..42,
                         name: "True",
                         arguments: [],
                         module: None,
@@ -28,18 +28,18 @@ Test(
                     annotation: None,
                 },
                 Var {
-                    location: 50..55,
+                    location: 54..59,
                     name: "False",
                 },
             ],
         },
         doc: None,
-        location: 0..22,
+        location: 0..26,
         name: "invalid_inputs",
         public: false,
         return_annotation: None,
         return_type: (),
-        end_position: 56,
+        end_position: 60,
         can_error: true,
     },
 )
diff --git a/crates/aiken-lang/src/parser/definition/test.rs b/crates/aiken-lang/src/parser/definition/test.rs
index 2516a9b4..0f56a443 100644
--- a/crates/aiken-lang/src/parser/definition/test.rs
+++ b/crates/aiken-lang/src/parser/definition/test.rs
@@ -7,20 +7,18 @@ use crate::{
 };
 
 pub fn parser() -> impl Parser<Token, ast::UntypedDefinition, Error = ParseError> {
-    just(Token::Bang)
-        .ignored()
-        .or_not()
-        .then_ignore(just(Token::Test))
-        .then(select! {Token::Name {name} => name})
+    just(Token::Test)
+        .ignore_then(select! {Token::Name {name} => name})
         .then_ignore(just(Token::LeftParen))
         .then_ignore(just(Token::RightParen))
+        .then(just(Token::Fail).ignored().or_not())
         .map_with_span(|name, span| (name, span))
         .then(
             expr::sequence()
                 .or_not()
                 .delimited_by(just(Token::LeftBrace), just(Token::RightBrace)),
         )
-        .map_with_span(|(((fail, name), span_end), body), span| {
+        .map_with_span(|(((name, fail), span_end), body), span| {
             ast::UntypedDefinition::Test(ast::Function {
                 arguments: vec![],
                 body: body.unwrap_or_else(|| UntypedExpr::todo(None, span)),
@@ -41,10 +39,10 @@ mod tests {
     use crate::assert_definition;
 
     #[test]
-    fn test_fail() {
+    fn def_test_fail() {
         assert_definition!(
             r#"
-            !test invalid_inputs() {
+            test invalid_inputs() fail {
               expect True = False
 
               False
diff --git a/crates/aiken-lang/src/tests/format.rs b/crates/aiken-lang/src/tests/format.rs
index ad2955ee..b720a5f6 100644
--- a/crates/aiken-lang/src/tests/format.rs
+++ b/crates/aiken-lang/src/tests/format.rs
@@ -507,12 +507,12 @@ fn test_format_match_record() {
 fn test_format_fail() {
     assert_format!(
         r#"
-      !test foo() {
-        expect Some(a) = bar
+        test foo() fail {
+          expect Some(a) = bar
 
-        a
-      }
-    "#
+          a
+        }
+        "#
     );
 }
 
diff --git a/crates/aiken-lang/src/tests/snapshots/format_fail.snap b/crates/aiken-lang/src/tests/snapshots/format_fail.snap
index d3fe7f08..c458504c 100644
--- a/crates/aiken-lang/src/tests/snapshots/format_fail.snap
+++ b/crates/aiken-lang/src/tests/snapshots/format_fail.snap
@@ -1,8 +1,8 @@
 ---
 source: crates/aiken-lang/src/tests/format.rs
-description: "Code:\n\n!test foo() {\n  expect Some(a) = bar\n\n  a\n}\n"
+description: "Code:\n\ntest foo() fail {\n  expect Some(a) = bar\n\n  a\n}\n"
 ---
-!test foo() {
+test foo() fail {
   expect Some(a) = bar
 
   a