test and fix display of zero-balance leaves (fixes #170)

hledger-lib/Hledger/Data/Account.hs

@@ -125,10 +125,11 @@ pruneAccounts :: (Account -> Bool) -> Account -> Maybe Account
 pruneAccounts p = headMay . prune
   where
     prune a
-      | null prunedsubs = if p a then [] else [a]
-      | otherwise       = [a{asubs=prunedsubs}]
+      | null prunedsubs = if p a then [] else [a']
+      | otherwise       = [a']
       where
         prunedsubs = concatMap prune $ asubs a
+        a' = a{asubs=prunedsubs}
 
 -- | Flatten an account tree into a list, which is sometimes
 -- convenient. Note since accounts link to their parents/subs, the

tests/balance-eliding.test

@@ -46,3 +46,15 @@ hledgerdev -f - balance --no-total
 >>>2
 >>>=0
 
+# 5. Zero-balance leaves should also be hidden by default.
+hledgerdev -f - balance --no-total
+<<<
+1/1
+ (a)          1
+ (a:aa)       1
+ (a:aa)      -1
+ (a:aa:aaa)   1
+ (a:aa:aaa)  -1
+>>>
+                   1  a
+>>>=0