tweak our number formatting function to be a bit more forgiving and treat...

tweak our number formatting function to be a bit more forgiving and treat decimals with no actual decimal values as if they are whole numbers.  also adding in some unit tests.

src/metabase/util.clj

@@ -119,12 +119,14 @@
   "format a number into a more human readable form."
   [number]
   {:pre [(number? number)]}
-  (if (or (float? number)
-          (decimal? number))
-    ;; looks like this is a decimal number, format with precision of 2
-    (format "%,.2f" number)
-    ;; otherwise expect this is a whole number
-    (format "%,d" number)))
+  (let [decimal-type? #(or (float? %) (decimal? %))]
+    (cond
+      ;; looks like this is a decimal number, format with precision of 2
+      (and (decimal-type? number) (not= 0 (mod number 1))) (format "%,.2f" number)
+      ;; this is a decimal type number with no actual decimal value, so treat it as a whole number
+      (decimal-type? number) (format "%,d" (long number))
+      ;; otherwise this is a whole number
+      :else (format "%,d" number))))
 
 (defn jdbc-clob->str
   "Convert a `JdbcClob` or `PGobject` to a `String`."

test/metabase/test_util.clj

@@ -46,6 +46,26 @@
   (host-port-up? "nosuchhost" 8005))
 
 
+;; ## tests for `(format-num)`
+
+(expect "1" (format-num 1))
+(expect "1" (format-num (float 1)))
+(expect "1" (format-num (double 1)))
+(expect "1" (format-num (bigdec 1)))
+(expect "1" (format-num (long 1)))
+(expect "1.23" (format-num (float 1.23444)))
+(expect "1.23" (format-num (double 1.23444)))
+(expect "1.23" (format-num (bigdec 1.23444)))
+(expect "1,234" (format-num 1234))
+(expect "1,234" (format-num (float 1234)))
+(expect "1,234" (format-num (double 1234)))
+(expect "1,234" (format-num (bigdec 1234)))
+(expect "1,234" (format-num (long 1234)))
+(expect "1,234.56" (format-num (float 1234.5678)))
+(expect "1,234.56" (format-num (double 1234.5678)))
+(expect "1,234.56" (format-num (bigdec 1234.5678)))
+
+
 ;;; ## tests for IS-URL?
 
 (expect true (is-url? "http://google.com"))