feat: Add Length Conversion (#1390)

Conversions/test/LengthConversion.test.js

@@ -0,0 +1,53 @@
+import { lengthConversion } from '../LengthConversion.js'
+
+describe('LengthConversion', () => {
+  it.each`
+    length | fromUnit | toUnit   | expected
+    ${10}  | ${'km'}  | ${'m'}   | ${10000}
+    ${100} | ${'m'}   | ${'km'}  | ${0.1}
+    ${5}   | ${'cm'}  | ${'mm'}  | ${50}
+    ${12}  | ${'ft'}  | ${'inch'}| ${144.00000000000003}
+  `(
+    'converts $length $fromUnit to $toUnit',
+    ({ length, fromUnit, toUnit, expected }) => {
+      try {
+        const result = lengthConversion(length, fromUnit, toUnit)
+        expect(result).toBe(expected)
+      } catch (error) {
+        expect(error).toBeUndefined()
+      }
+    }
+  )
+
+  it.each`
+    length | fromUnit | toUnit   | expected
+    ${10}  | ${'m'}   | ${'km'}  | ${0.01}
+    ${1000}| ${'mm'}  | ${'cm'}  | ${100}
+    ${1}   | ${'inch'}| ${'ft'}  | ${0.08333333333}
+  `(
+    'converts $length $fromUnit to $toUnit (vice versa)',
+    ({ length, fromUnit, toUnit, expected }) => {
+      try {
+        const result = lengthConversion(length, fromUnit, toUnit)
+        expect(result).toBeCloseTo(expected, 10) // Close comparison due to floating-point precision
+      } catch (error) {
+        expect(error).toBeUndefined()
+      }
+    }
+  )
+
+  it.each`
+    length | fromUnit | toUnit     | expectedError
+    ${10}  | ${'km'}  | ${'invalid'} | ${'Invalid units'}
+    ${5}   | ${'invalid'} | ${'m'}    | ${'Invalid units'}
+  `(
+    'returns error message for invalid units: $fromUnit to $toUnit',
+    ({ length, fromUnit, toUnit, expectedError }) => {
+      try {
+        lengthConversion(length, fromUnit, toUnit)
+      } catch (error) {
+        expect(error.message).toBe(expectedError)
+      }
+    }
+  )
+})