From 2014dffd27909c753fa9e237e3c1132b68537f33 Mon Sep 17 00:00:00 2001
From: teor <teor@riseup.net>
Date: Thu, 3 Dec 2020 14:56:19 +1000
Subject: [PATCH] Show expanded values in CompactDifficulty debug fmt

---
 zebra-chain/src/work/difficulty.rs            |  4 ++++
 .../src/work/difficulty/tests/vectors.rs      | 20 ++++++++++++++++---
 2 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/zebra-chain/src/work/difficulty.rs b/zebra-chain/src/work/difficulty.rs
index e6303cee..229af40e 100644
--- a/zebra-chain/src/work/difficulty.rs
+++ b/zebra-chain/src/work/difficulty.rs
@@ -63,9 +63,13 @@ pub struct CompactDifficulty(pub(crate) u32);
 
 impl fmt::Debug for CompactDifficulty {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        // There isn't a standard way to represent alternate formats for the
+        // same value.
         f.debug_tuple("CompactDifficulty")
             // Use hex, because it's a float
             .field(&format_args!("{:#010x}", self.0))
+            // Use expanded difficulty, for bitwise difficulty comparisons
+            .field(&format_args!("{:?}", self.to_expanded()))
             .finish()
     }
 }
diff --git a/zebra-chain/src/work/difficulty/tests/vectors.rs b/zebra-chain/src/work/difficulty/tests/vectors.rs
index 1d07acf2..5a9c33fe 100644
--- a/zebra-chain/src/work/difficulty/tests/vectors.rs
+++ b/zebra-chain/src/work/difficulty/tests/vectors.rs
@@ -19,15 +19,29 @@ fn debug_format() {
 
     assert_eq!(
         format!("{:?}", CompactDifficulty(0)),
-        "CompactDifficulty(0x00000000)"
+        "CompactDifficulty(0x00000000, None)"
     );
     assert_eq!(
         format!("{:?}", CompactDifficulty(1)),
-        "CompactDifficulty(0x00000001)"
+        "CompactDifficulty(0x00000001, None)"
     );
     assert_eq!(
         format!("{:?}", CompactDifficulty(u32::MAX)),
-        "CompactDifficulty(0xffffffff)"
+        "CompactDifficulty(0xffffffff, None)"
+    );
+    let one = CompactDifficulty((1 << PRECISION) + (1 << 16));
+    assert_eq!(
+        format!("{:?}", one),
+        "CompactDifficulty(0x01010000, Some(ExpandedDifficulty(\"0000000000000000000000000000000000000000000000000000000000000001\")))");
+    let mant = CompactDifficulty(OFFSET as u32 * (1 << PRECISION) + UNSIGNED_MANTISSA_MASK);
+    assert_eq!(
+        format!("{:?}", mant),
+        "CompactDifficulty(0x037fffff, Some(ExpandedDifficulty(\"00000000000000000000000000000000000000000000000000000000007fffff\")))"
+    );
+    let exp = CompactDifficulty(((31 + OFFSET - 2) as u32) * (1 << PRECISION) + (1 << 16));
+    assert_eq!(
+        format!("{:?}", exp),
+        "CompactDifficulty(0x20010000, Some(ExpandedDifficulty(\"0100000000000000000000000000000000000000000000000000000000000000\")))"
     );
 
     assert_eq!(