update calculations for lucky levels (#1161)

* update calculations for lucky levels

* [pre-commit.ci] auto fixes from pre-commit.com hooks

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---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

test/t_Disp/t_CalculateLuckyLevels.js

@@ -0,0 +1,65 @@
+import { describe, it } from 'mocha';
+import { expect } from 'chai';
+
+import CalculateLuckyLevels, {
+  CalculateSevenDelta,
+  CountSevens,
+} from '../../src/Disp/HelperFunctions/CalculateLuckyLevels';
+
+describe('CountSevens', () => {
+  const examples = [
+    { input: 1234567890, output: 1 },
+    { input: 7777777777, output: 10 },
+    { input: 1111111111, output: 0 },
+    { input: 7897897897, output: 4 },
+  ];
+
+  examples.forEach((example) => {
+    it(`Counts sevens in ${example.input}`, () => {
+      expect(CountSevens(example.input)).to.equal(example.output);
+    });
+  });
+});
+
+describe('CalculateSevenDelta', () => {
+  const examples = [
+    { number: 123, digit: 1, output: 4 },
+    { number: 123, digit: 10, output: 50 },
+    { number: 123, digit: 100, output: 600 },
+    { number: 123, digit: 1000, output: 7000 },
+    { number: 7777, digit: 1, output: 0 },
+    { number: 7777, digit: 10, output: 0 },
+    { number: 7777, digit: 100, output: 0 },
+    { number: 7777, digit: 1000, output: 0 },
+    { number: 9999, digit: 1, output: 8 },
+    { number: 9999, digit: 10, output: 80 },
+    { number: 9999, digit: 100, output: 800 },
+    { number: 9999, digit: 1000, output: 8000 },
+  ];
+
+  examples.forEach((example) => {
+    it(`Calculates delta from ${example.number} to the next 7 in the ${example.digit}s digit`, () => {
+      expect(CalculateSevenDelta(example.number, example.digit)).to.equal(example.output);
+    });
+  });
+});
+
+describe('CalculateLuckyLevels', () => {
+  const examples = [
+    { input: 0, luckyDigit: 7, luckyNumber: 77, luckyPayout: 7777 },
+    { input: 123, luckyDigit: 127, luckyNumber: 177, luckyPayout: 7777 },
+    { input: 77777, luckyDigit: 77777, luckyNumber: 77777, luckyPayout: 77777 },
+    { input: 799999, luckyDigit: 799999, luckyNumber: 800077, luckyPayout: 807777 },
+    { input: 999999, luckyDigit: 1000007, luckyNumber: 1000077, luckyPayout: 1007777 },
+  ];
+
+  examples.forEach((example) => {
+    it(`Calculates the next lucky levels for the starting level ${example.input}`, () => {
+      expect(CalculateLuckyLevels(example.input)).to.deep.equal({
+        luckyDigit: example.luckyDigit,
+        luckyNumber: example.luckyNumber,
+        luckyPayout: example.luckyPayout,
+      });
+    });
+  });
+});