diff --git a/boa_ast/src/keyword.rs b/boa_ast/src/keyword/mod.rs
similarity index 99%
rename from boa_ast/src/keyword.rs
rename to boa_ast/src/keyword/mod.rs
index 8ded9b6d38..f1c36ec113 100644
--- a/boa_ast/src/keyword.rs
+++ b/boa_ast/src/keyword/mod.rs
@@ -14,6 +14,9 @@ use boa_interner::Sym;
 use boa_macros::utf16;
 use std::{convert::TryFrom, error, fmt, str::FromStr};
 
+#[cfg(test)]
+mod tests;
+
 /// List of keywords recognized by the JavaScript grammar.
 ///
 /// See the [module-level documentation][self] for more details.
@@ -604,11 +607,8 @@ impl fmt::Display for KeywordError {
 }
 
 // This is important for other errors to wrap this one.
-impl error::Error for KeywordError {
-    fn description(&self) -> &str {
-        "invalid token"
-    }
-}
+impl error::Error for KeywordError {}
+
 impl FromStr for Keyword {
     type Err = KeywordError;
     fn from_str(s: &str) -> Result<Self, Self::Err> {
diff --git a/boa_ast/src/keyword/tests.rs b/boa_ast/src/keyword/tests.rs
new file mode 100644
index 0000000000..182f685e65
--- /dev/null
+++ b/boa_ast/src/keyword/tests.rs
@@ -0,0 +1,354 @@
+#![allow(clippy::cognitive_complexity)]
+
+use super::*;
+
+/// Gets a list of all the keywords.
+fn all_keywords() -> impl Iterator<Item = Keyword> {
+    [
+        Keyword::Await,
+        Keyword::Async,
+        Keyword::Break,
+        Keyword::Case,
+        Keyword::Catch,
+        Keyword::Class,
+        Keyword::Continue,
+        Keyword::Const,
+        Keyword::Debugger,
+        Keyword::Default,
+        Keyword::Delete,
+        Keyword::Do,
+        Keyword::Else,
+        Keyword::Enum,
+        Keyword::Export,
+        Keyword::Extends,
+        Keyword::False,
+        Keyword::Finally,
+        Keyword::For,
+        Keyword::Function,
+        Keyword::If,
+        Keyword::In,
+        Keyword::InstanceOf,
+        Keyword::Import,
+        Keyword::Let,
+        Keyword::New,
+        Keyword::Null,
+        Keyword::Of,
+        Keyword::Return,
+        Keyword::Super,
+        Keyword::Switch,
+        Keyword::This,
+        Keyword::Throw,
+        Keyword::True,
+        Keyword::Try,
+        Keyword::TypeOf,
+        Keyword::Var,
+        Keyword::Void,
+        Keyword::While,
+        Keyword::With,
+        Keyword::Yield,
+    ]
+    .into_iter()
+}
+
+#[test]
+fn as_binary_op() {
+    for k in all_keywords() {
+        match k.as_binary_op() {
+            Some(BinaryOp::Relational(RelationalOp::InstanceOf)) => {
+                assert_eq!(k, Keyword::InstanceOf);
+            }
+            Some(BinaryOp::Relational(RelationalOp::In)) => assert_eq!(k, Keyword::In),
+            None => {
+                assert_ne!(k, Keyword::InstanceOf);
+                assert_ne!(k, Keyword::In);
+            }
+            _ => unreachable!("unknown binary operator for keyword {k:?} found"),
+        }
+    }
+}
+
+#[test]
+fn as_str() {
+    for k in all_keywords() {
+        match k.as_str() {
+            ("await", utf16) => {
+                assert_eq!(k, Keyword::Await);
+                assert_eq!(utf16, utf16!("await"));
+            }
+            ("async", utf16) => {
+                assert_eq!(k, Keyword::Async);
+                assert_eq!(utf16, utf16!("async"));
+            }
+            ("break", utf16) => {
+                assert_eq!(k, Keyword::Break);
+                assert_eq!(utf16, utf16!("break"));
+            }
+            ("case", utf16) => {
+                assert_eq!(k, Keyword::Case);
+                assert_eq!(utf16, utf16!("case"));
+            }
+            ("catch", utf16) => {
+                assert_eq!(k, Keyword::Catch);
+                assert_eq!(utf16, utf16!("catch"));
+            }
+            ("class", utf16) => {
+                assert_eq!(k, Keyword::Class);
+                assert_eq!(utf16, utf16!("class"));
+            }
+            ("continue", utf16) => {
+                assert_eq!(k, Keyword::Continue);
+                assert_eq!(utf16, utf16!("continue"));
+            }
+            ("const", utf16) => {
+                assert_eq!(k, Keyword::Const);
+                assert_eq!(utf16, utf16!("const"));
+            }
+            ("debugger", utf16) => {
+                assert_eq!(k, Keyword::Debugger);
+                assert_eq!(utf16, utf16!("debugger"));
+            }
+            ("default", utf16) => {
+                assert_eq!(k, Keyword::Default);
+                assert_eq!(utf16, utf16!("default"));
+            }
+            ("delete", utf16) => {
+                assert_eq!(k, Keyword::Delete);
+                assert_eq!(utf16, utf16!("delete"));
+            }
+            ("do", utf16) => {
+                assert_eq!(k, Keyword::Do);
+                assert_eq!(utf16, utf16!("do"));
+            }
+            ("else", utf16) => {
+                assert_eq!(k, Keyword::Else);
+                assert_eq!(utf16, utf16!("else"));
+            }
+            ("enum", utf16) => {
+                assert_eq!(k, Keyword::Enum);
+                assert_eq!(utf16, utf16!("enum"));
+            }
+            ("extends", utf16) => {
+                assert_eq!(k, Keyword::Extends);
+                assert_eq!(utf16, utf16!("extends"));
+            }
+            ("export", utf16) => {
+                assert_eq!(k, Keyword::Export);
+                assert_eq!(utf16, utf16!("export"));
+            }
+            ("false", utf16) => {
+                assert_eq!(k, Keyword::False);
+                assert_eq!(utf16, utf16!("false"));
+            }
+            ("finally", utf16) => {
+                assert_eq!(k, Keyword::Finally);
+                assert_eq!(utf16, utf16!("finally"));
+            }
+            ("for", utf16) => {
+                assert_eq!(k, Keyword::For);
+                assert_eq!(utf16, utf16!("for"));
+            }
+            ("function", utf16) => {
+                assert_eq!(k, Keyword::Function);
+                assert_eq!(utf16, utf16!("function"));
+            }
+            ("if", utf16) => {
+                assert_eq!(k, Keyword::If);
+                assert_eq!(utf16, utf16!("if"));
+            }
+            ("in", utf16) => {
+                assert_eq!(k, Keyword::In);
+                assert_eq!(utf16, utf16!("in"));
+            }
+            ("instanceof", utf16) => {
+                assert_eq!(k, Keyword::InstanceOf);
+                assert_eq!(utf16, utf16!("instanceof"));
+            }
+            ("import", utf16) => {
+                assert_eq!(k, Keyword::Import);
+                assert_eq!(utf16, utf16!("import"));
+            }
+            ("let", utf16) => {
+                assert_eq!(k, Keyword::Let);
+                assert_eq!(utf16, utf16!("let"));
+            }
+            ("new", utf16) => {
+                assert_eq!(k, Keyword::New);
+                assert_eq!(utf16, utf16!("new"));
+            }
+            ("null", utf16) => {
+                assert_eq!(k, Keyword::Null);
+                assert_eq!(utf16, utf16!("null"));
+            }
+            ("of", utf16) => {
+                assert_eq!(k, Keyword::Of);
+                assert_eq!(utf16, utf16!("of"));
+            }
+            ("return", utf16) => {
+                assert_eq!(k, Keyword::Return);
+                assert_eq!(utf16, utf16!("return"));
+            }
+            ("super", utf16) => {
+                assert_eq!(k, Keyword::Super);
+                assert_eq!(utf16, utf16!("super"));
+            }
+            ("switch", utf16) => {
+                assert_eq!(k, Keyword::Switch);
+                assert_eq!(utf16, utf16!("switch"));
+            }
+            ("this", utf16) => {
+                assert_eq!(k, Keyword::This);
+                assert_eq!(utf16, utf16!("this"));
+            }
+            ("throw", utf16) => {
+                assert_eq!(k, Keyword::Throw);
+                assert_eq!(utf16, utf16!("throw"));
+            }
+            ("true", utf16) => {
+                assert_eq!(k, Keyword::True);
+                assert_eq!(utf16, utf16!("true"));
+            }
+            ("try", utf16) => {
+                assert_eq!(k, Keyword::Try);
+                assert_eq!(utf16, utf16!("try"));
+            }
+            ("typeof", utf16) => {
+                assert_eq!(k, Keyword::TypeOf);
+                assert_eq!(utf16, utf16!("typeof"));
+            }
+            ("var", utf16) => {
+                assert_eq!(k, Keyword::Var);
+                assert_eq!(utf16, utf16!("var"));
+            }
+            ("void", utf16) => {
+                assert_eq!(k, Keyword::Void);
+                assert_eq!(utf16, utf16!("void"));
+            }
+            ("while", utf16) => {
+                assert_eq!(k, Keyword::While);
+                assert_eq!(utf16, utf16!("while"));
+            }
+            ("with", utf16) => {
+                assert_eq!(k, Keyword::With);
+                assert_eq!(utf16, utf16!("with"));
+            }
+            ("yield", utf16) => {
+                assert_eq!(k, Keyword::Yield);
+                assert_eq!(utf16, utf16!("yield"));
+            }
+            (_, _) => unreachable!("unknown keyword {k:?} found"),
+        }
+    }
+}
+
+#[test]
+fn to_sym() {
+    for k in all_keywords() {
+        match k.to_sym() {
+            Sym::AWAIT => assert_eq!(k, Keyword::Await),
+            Sym::ASYNC => assert_eq!(k, Keyword::Async),
+            Sym::BREAK => assert_eq!(k, Keyword::Break),
+            Sym::CASE => assert_eq!(k, Keyword::Case),
+            Sym::CATCH => assert_eq!(k, Keyword::Catch),
+            Sym::CLASS => assert_eq!(k, Keyword::Class),
+            Sym::CONTINUE => assert_eq!(k, Keyword::Continue),
+            Sym::CONST => assert_eq!(k, Keyword::Const),
+            Sym::DEBUGGER => assert_eq!(k, Keyword::Debugger),
+            Sym::DEFAULT => assert_eq!(k, Keyword::Default),
+            Sym::DELETE => assert_eq!(k, Keyword::Delete),
+            Sym::DO => assert_eq!(k, Keyword::Do),
+            Sym::ELSE => assert_eq!(k, Keyword::Else),
+            Sym::ENUM => assert_eq!(k, Keyword::Enum),
+            Sym::EXPORT => assert_eq!(k, Keyword::Export),
+            Sym::EXTENDS => assert_eq!(k, Keyword::Extends),
+            Sym::FALSE => assert_eq!(k, Keyword::False),
+            Sym::FINALLY => assert_eq!(k, Keyword::Finally),
+            Sym::FOR => assert_eq!(k, Keyword::For),
+            Sym::FUNCTION => assert_eq!(k, Keyword::Function),
+            Sym::IF => assert_eq!(k, Keyword::If),
+            Sym::IN => assert_eq!(k, Keyword::In),
+            Sym::INSTANCEOF => assert_eq!(k, Keyword::InstanceOf),
+            Sym::IMPORT => assert_eq!(k, Keyword::Import),
+            Sym::LET => assert_eq!(k, Keyword::Let),
+            Sym::NEW => assert_eq!(k, Keyword::New),
+            Sym::NULL => assert_eq!(k, Keyword::Null),
+            Sym::OF => assert_eq!(k, Keyword::Of),
+            Sym::RETURN => assert_eq!(k, Keyword::Return),
+            Sym::SUPER => assert_eq!(k, Keyword::Super),
+            Sym::SWITCH => assert_eq!(k, Keyword::Switch),
+            Sym::THIS => assert_eq!(k, Keyword::This),
+            Sym::THROW => assert_eq!(k, Keyword::Throw),
+            Sym::TRUE => assert_eq!(k, Keyword::True),
+            Sym::TRY => assert_eq!(k, Keyword::Try),
+            Sym::TYPEOF => assert_eq!(k, Keyword::TypeOf),
+            Sym::VAR => assert_eq!(k, Keyword::Var),
+            Sym::VOID => assert_eq!(k, Keyword::Void),
+            Sym::WHILE => assert_eq!(k, Keyword::While),
+            Sym::WITH => assert_eq!(k, Keyword::With),
+            Sym::YIELD => assert_eq!(k, Keyword::Yield),
+            _ => unreachable!("unknown keyword {k:?} found"),
+        }
+    }
+}
+
+#[test]
+fn try_into_binary_op() {
+    for k in all_keywords() {
+        match k {
+            Keyword::InstanceOf | Keyword::In => assert!(BinaryOp::try_from(k).is_ok()),
+            Keyword::Await
+            | Keyword::Async
+            | Keyword::Break
+            | Keyword::Case
+            | Keyword::Catch
+            | Keyword::Class
+            | Keyword::Continue
+            | Keyword::Const
+            | Keyword::Debugger
+            | Keyword::Default
+            | Keyword::Delete
+            | Keyword::Do
+            | Keyword::Else
+            | Keyword::Enum
+            | Keyword::Export
+            | Keyword::Extends
+            | Keyword::False
+            | Keyword::Finally
+            | Keyword::For
+            | Keyword::Function
+            | Keyword::If
+            | Keyword::Import
+            | Keyword::Let
+            | Keyword::New
+            | Keyword::Null
+            | Keyword::Of
+            | Keyword::Return
+            | Keyword::Super
+            | Keyword::Switch
+            | Keyword::This
+            | Keyword::Throw
+            | Keyword::True
+            | Keyword::Try
+            | Keyword::TypeOf
+            | Keyword::Var
+            | Keyword::Void
+            | Keyword::While
+            | Keyword::With
+            | Keyword::Yield => assert!(BinaryOp::try_from(k).is_err()),
+        }
+    }
+}
+
+#[test]
+fn from_str() {
+    for k in all_keywords() {
+        let str = k.as_str().0;
+        assert_eq!(str.parse::<Keyword>().unwrap(), k);
+    }
+
+    for invalid in ["", "testing", "invalid keyword"] {
+        let result = invalid.parse::<Keyword>();
+        let error = result.unwrap_err();
+
+        assert_eq!(error.to_string(), "invalid token");
+    }
+}