activity: fix output after #1982; add tests

hledger/Hledger/Cli/Commands/Activity.hs

@@ -43,7 +43,7 @@ showHistogram rspec@ReportSpec{_rsQuery=q} j =
     -- ps = sortBy (comparing postingDate) $ filterempties $ filter matchapats $ filterdepth $ journalPostings j
     ps = sortOn postingDate $ filter (q `matchesPosting`) $ journalPostings j
 
-printDayWith f (DateSpan (Just b) _, ps) = printf "%s %s\n" (show b) (f ps)
+printDayWith f (DateSpan (Just b) _, ps) = printf "%s %s\n" (show $ fromEFDay b) (f ps)
 printDayWith _ _ = error "Expected start date for DateSpan"  -- PARTIAL:
 
 countBar ps = replicate (length ps) barchar

hledger/test/activity.test

@@ -0,0 +1,38 @@
+# 1. activity report is daily by default.
+<
+2023-01-01
+  (a)  1
+
+2023-01-06
+  (a)  1
+
+$ hledger -f - activity
+2023-01-01 *
+2023-01-02 
+2023-01-03 
+2023-01-04 
+2023-01-05 
+2023-01-06 *
+
+# 2. A weekly activity report.
+<
+2023-01-01
+  (a)  1
+
+2023-01-06
+  (a)  1
+
+$ hledger -f - activity -W
+2022-12-26 *
+2023-01-02 *
+
+# 2. A 7-day activity report starting on an date.
+<
+2023-01-01
+  (a)  1
+
+2023-01-06
+  (a)  1
+
+$ hledger -f - activity -W -b2023-01-01
+2023-01-01 **