Fix a bug in order-of-magnitude (x<=0) and moved it to util

src/metabase/query_processor/middleware/binning.clj

@@ -71,16 +71,12 @@
   (let [scale (/ precision)]
     (/ (floor (* x scale)) scale)))
 
-(defn- order-of-magnitude
-  [x]
-  (floor (/ (Math/log x) (Math/log 10))))
-
 (def ^:private ^:const pleasing-numbers [1 1.25 2 2.5 3 5 7.5 10])
 
 (defn- nicer-bin-width
   [min-value max-value num-bins]
   (let [min-bin-width (calculate-bin-width min-value max-value num-bins)
-        scale         (expt 10 (order-of-magnitude min-bin-width))]
+        scale         (expt 10 (u/order-of-magnitude min-bin-width))]
     (->> pleasing-numbers
          (map (partial * scale))
          (drop-while (partial > min-bin-width))

src/metabase/util.clj

@@ -880,3 +880,11 @@
   [m & {:keys [present non-nil]}]
   (merge (select-keys m present)
          (select-non-nil-keys m non-nil)))
+
+(defn order-of-magnitude
+  "Return the order of magnitude as a power of 10 of a given number."
+  [x]
+  (if (zero? x)
+    0
+    (long (math/floor (/ (Math/log (math/abs x))
+                         (Math/log 10))))))

test/metabase/query_processor/middleware/binning_test.clj

@@ -32,11 +32,6 @@
    (mapv (partial ceil-to 1.0) [1 1.1 1.8])
    (mapv (partial ceil-to 15.0) [1.0 15.0 16.0])])
 
-
-(expect
-  [-2.0 -1.0 0.0 1.0 2.0 3.0]
-  (map order-of-magnitude [0.01 0.5 4 12 444 1023]))
-
 (expect
   [20.0 2000.0]
   [(nicer-bin-width 27 135 8)

test/metabase/util_test.clj

@@ -242,3 +242,7 @@
   (select-keys-when {:a 100, :b nil, :d 200, :e nil}
     :present #{:a :b :c}
     :non-nil #{:d :e :f}))
+
+(expect
+  [-2 -1 0 1 2 3 0 3]
+  (map order-of-magnitude [0.01 0.5 4 12 444 1023 0 -1444]))