Add additional test and refactor a bit

Author: camdecoster

test/jasmine/tests/axes_test.js

@@ -14,10 +14,7 @@ var Cartesian = require('../../../src/plots/cartesian');
 var Axes = require('../../../src/plots/cartesian/axes');
 var Fx = require('../../../src/components/fx');
 var supplyLayoutDefaults = require('../../../src/plots/cartesian/layout_defaults');
-var numerical = require('../../../src/constants/numerical');
-var BADNUM = numerical.BADNUM;
-var ONEDAY = numerical.ONEDAY;
-var ONEWEEK = numerical.ONEWEEK;
+const {BADNUM, MINUS_SIGN, ONEDAY, ONEWEEK} = require('../../../src/constants/numerical');
 
 var createGraphDiv = require('../assets/create_graph_div');
 var destroyGraphDiv = require('../assets/destroy_graph_div');
@@ -3502,29 +3499,50 @@ describe('Test axes', function() {
             ]);
         });
 
-        it('snaps a near-zero tick to exactly tick0 so d3-format specs do not show float artefacts (issue 7765)', function() {
-            // With this range the increments accumulate a roundoff error and the
-            // tick that should be exactly 0 comes out as ~-8.9e-17. The default
-            // format rounds that away, but `~r` would render it literally as
-            // -0.0000000000000000888178 without the snap-to-tick0 correction.
-            var spec = {
+        it('snaps a near-zero tick to exactly tick0', () => {
+            const spec = {
                 type: 'linear',
                 tickmode: 'linear',
                 tick0: 0,
                 dtick: 0.2,
                 range: [-0.65, 0.65]
             };
 
-            expect(mockCalc(Lib.extendDeep({}, spec, {tickformat: '~r'}))).toEqual([
-                '−0.6', '−0.4', '−0.2', '0', '0.2', '0.4', '0.6'
+            expect(mockCalc({ ...spec, tickformat: '~r' })).toEqual([
+                MINUS_SIGN + '0.6',
+                MINUS_SIGN + '0.4',
+                MINUS_SIGN + '0.2',
+                '0',
+                '0.2',
+                '0.4',
+                '0.6'
             ]);
 
             // the default numeric format was already fine; make sure it stays fine
-            expect(mockCalc(Lib.extendDeep({}, spec))).toEqual([
-                '−0.6', '−0.4', '−0.2', '0', '0.2', '0.4', '0.6'
+            expect(mockCalc(spec)).toEqual([
+                MINUS_SIGN + '0.6',
+                MINUS_SIGN + '0.4',
+                MINUS_SIGN + '0.2',
+                '0',
+                '0.2',
+                '0.4',
+                '0.6'
             ]);
         });
 
+        it('snaps ticks to non-tick0 grid positions', () => {
+            const textOut = mockCalc({
+                type: 'linear',
+                tickmode: 'linear',
+                tick0: 1,
+                dtick: 0.1,
+                range: [-0.05, 0.05],
+                tickformat: '~r'
+            });
+
+            expect(textOut).toEqual(['0']);
+        });
+
         it('reverts to "power" for SI/B exponentformat beyond the prefix range (log case)', function() {
             var textOut = mockCalc({
                 type: 'log',