1 files changed, 54 insertions, 0 deletions
diff --git a/third_party/rust/serde_json/tests/lexical/exponent.rs b/third_party/rust/serde_json/tests/lexical/exponent.rs
new file mode 100644
index 0000000000..f7a847be38
--- /dev/null
+++ b/third_party/rust/serde_json/tests/lexical/exponent.rs
@@ -0,0 +1,54 @@
+// Adapted from https://github.com/Alexhuszagh/rust-lexical.
+
+use crate::lexical::exponent::*;
+
+#[test]
+fn scientific_exponent_test() {
+    // 0 digits in the integer
+    assert_eq!(scientific_exponent(0, 0, 5), -6);
+    assert_eq!(scientific_exponent(10, 0, 5), 4);
+    assert_eq!(scientific_exponent(-10, 0, 5), -16);
+
+    // >0 digits in the integer
+    assert_eq!(scientific_exponent(0, 1, 5), 0);
+    assert_eq!(scientific_exponent(0, 2, 5), 1);
+    assert_eq!(scientific_exponent(0, 2, 20), 1);
+    assert_eq!(scientific_exponent(10, 2, 20), 11);
+    assert_eq!(scientific_exponent(-10, 2, 20), -9);
+
+    // Underflow
+    assert_eq!(
+        scientific_exponent(i32::min_value(), 0, 0),
+        i32::min_value()
+    );
+    assert_eq!(
+        scientific_exponent(i32::min_value(), 0, 5),
+        i32::min_value()
+    );
+
+    // Overflow
+    assert_eq!(
+        scientific_exponent(i32::max_value(), 0, 0),
+        i32::max_value() - 1
+    );
+    assert_eq!(
+        scientific_exponent(i32::max_value(), 5, 0),
+        i32::max_value()
+    );
+}
+
+#[test]
+fn mantissa_exponent_test() {
+    assert_eq!(mantissa_exponent(10, 5, 0), 5);
+    assert_eq!(mantissa_exponent(0, 5, 0), -5);
+    assert_eq!(
+        mantissa_exponent(i32::max_value(), 5, 0),
+        i32::max_value() - 5
+    );
+    assert_eq!(mantissa_exponent(i32::max_value(), 0, 5), i32::max_value());
+    assert_eq!(mantissa_exponent(i32::min_value(), 5, 0), i32::min_value());
+    assert_eq!(
+        mantissa_exponent(i32::min_value(), 0, 5),
+        i32::min_value() + 5
+    );
+}