diff --git a/src/lib.rs b/src/lib.rs
index a127619..0fd4ed5 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -12,6 +12,7 @@ pub use parser::{ParseResult, Parser};
 mod tests {
     use super::*;
     use crate::choice::choice;
+    use crate::combinators::{one_or_more, zero_or_more};
     use crate::primitives::{any_char, literal, literal_char, one_of, pred};
     use crate::sequence::seq;
     use std::collections::HashMap;
@@ -48,8 +49,45 @@ mod tests {
             literal("false").to(JsonValue::Bool(false)),
         ));
 
-        let digit = one_of("1234567890");
-        assert_eq!(digit.parse("3"), Ok(("3", "")));
+        let digit = || one_of("1234567890");
+        assert_eq!(digit().parse("3"), Ok(("3", "")));
+
+        let json_number_inner = choice((
+            seq((
+                one_or_more(digit()),
+                literal(".").then(zero_or_more(digit())).optional(),
+            ))
+            .map(|(mut digits, maybe_more)| {
+                if let Some((point, more)) = maybe_more {
+                    digits.push(point);
+                    digits.extend(more.into_iter());
+                }
+                digits.into_iter().collect::<String>()
+            }),
+            seq((literal("."), one_or_more(digit()))).map(|(_point, digits)| {
+                let mut d = vec!["."];
+                d.extend(digits.into_iter());
+                d.into_iter().collect::<String>()
+            }),
+        ))
+        .map(|digits| digits.parse::<f64>().unwrap());
+
+        let json_number =
+            literal("-")
+                .optional()
+                .then(json_number_inner)
+                .map(|(maybe_sign, val)| {
+                    if maybe_sign.is_some() {
+                        val * -1.0
+                    } else {
+                        val
+                    }
+                });
+
+        assert_eq!(json_number.parse("-383").unwrap().0, -383f64);
+        assert_eq!(json_number.parse("-.383").unwrap().0, -0.383);
+        assert_eq!(json_number.parse(".383").unwrap().0, 0.383);
+        assert_eq!(json_number.parse("-1.383").unwrap().0, -1.383);
 
         let json_string = seq((
             literal_char('"'),