From 4aaf911142fd86e15d1add004cc14bc92cfecf73 Mon Sep 17 00:00:00 2001
From: Parth Desai <desaiparth08@gmail.com>
Date: Thu, 14 Nov 2019 09:53:36 +0530
Subject: [PATCH] fix bug + more precise test

---
 sdk/src/rent.rs | 38 ++++++++++++++++++++++++++++++--------
 1 file changed, 30 insertions(+), 8 deletions(-)

diff --git a/sdk/src/rent.rs b/sdk/src/rent.rs
index 502e0c24acb6b9..b0914d52049f93 100644
--- a/sdk/src/rent.rs
+++ b/sdk/src/rent.rs
@@ -43,7 +43,7 @@ impl Rent {
     /// minimum balance due for a given size Account::data.len()
     pub fn minimum_balance(&self, data_len: usize) -> u64 {
         let bytes = data_len as u64;
-        (((ACCOUNT_STORAGE_OVERHEAD * bytes) * self.lamports_per_byte_year) as f64
+        (((ACCOUNT_STORAGE_OVERHEAD + bytes) * self.lamports_per_byte_year) as f64
             * self.exemption_threshold) as u64
     }
 
@@ -80,20 +80,42 @@ mod tests {
 
     #[test]
     fn test_due() {
-        let rent = Rent::default();
+        let default_rent = Rent::default();
 
         assert_eq!(
-            rent.due(0, 1, 1.0),
+            default_rent.due(0, 2, 1.0),
             (
-                (1 + ACCOUNT_STORAGE_OVERHEAD) * DEFAULT_LAMPORTS_PER_BYTE_YEAR,
+                (2 + ACCOUNT_STORAGE_OVERHEAD) * DEFAULT_LAMPORTS_PER_BYTE_YEAR,
                 DEFAULT_LAMPORTS_PER_BYTE_YEAR == 0
             )
         );
         assert_eq!(
-            rent.due(
-                ((1 + ACCOUNT_STORAGE_OVERHEAD) * DEFAULT_LAMPORTS_PER_BYTE_YEAR)
-                    * DEFAULT_EXEMPTION_THRESHOLD as u64,
-                1,
+            default_rent.due(
+                (((2 + ACCOUNT_STORAGE_OVERHEAD) * DEFAULT_LAMPORTS_PER_BYTE_YEAR) as f64
+                    * DEFAULT_EXEMPTION_THRESHOLD) as u64,
+                2,
+                1.0
+            ),
+            (0, true)
+        );
+
+        let mut custom_rent = Rent::default();
+        custom_rent.lamports_per_byte_year = 5;
+        custom_rent.exemption_threshold = 2.5;
+
+        assert_eq!(
+            custom_rent.due(0, 2, 1.0),
+            (
+                (2 + ACCOUNT_STORAGE_OVERHEAD) * custom_rent.lamports_per_byte_year,
+                false
+            )
+        );
+
+        assert_eq!(
+            custom_rent.due(
+                (((2 + ACCOUNT_STORAGE_OVERHEAD) * custom_rent.lamports_per_byte_year) as f64
+                    * custom_rent.exemption_threshold) as u64,
+                2,
                 1.0
             ),
             (0, true)