add some tests and update the deadme for the code

README.md

@@ -39,4 +39,19 @@ A simple SLI/SLO calculator that allows playing with different parameters to see
 
 ---
 
+# Code
+
+Like most of my hobby projects, this repo wasn't meant to grow this big.
+It started as a single page application to compensate some shortcomings
+I faced when using [uptime.is](https://uptime.is) with these preconditions:
+
+1. No transpilation whatsoever ([because](https://medium.com/free-code-camp/you-might-not-need-to-transpile-your-javascript-4d5e0a438ca))
+2. Use the latest version of Vue (to learn it)
+3. Run tests with Deno (to learn it)
+4. Use Github Copilot assistence (to learn it)
+
+And here we are.
+
+---
+
 Made by [Alex Ewerlöf](https://www.alexewerlof.com)

lib/math_test.js

@@ -0,0 +1,33 @@
+import { assertEquals, assertThrows } from "https://deno.land/std/testing/asserts.ts"
+import { percent, percentToRatio, toFixed, clamp } from "./math.js"
+
+Deno.test("percent", () => {
+    assertEquals(percent(50, 200), 100)
+    assertEquals(percent(25, 80), 20)
+    assertEquals(percent(75, 120), 90)
+})
+
+Deno.test("percent throws error for invalid input", () => {
+    assertThrows(() => percent("50", 200))
+    assertThrows(() => percent(50, "200"))
+    assertThrows(() => percent(150, 200))
+    assertThrows(() => percent(-50, 200))
+})
+
+Deno.test("percentToRatio", () => {
+    assertEquals(percentToRatio(50), 0.5)
+    assertEquals(percentToRatio(25), 0.25)
+    assertEquals(percentToRatio(75), 0.75)
+})
+
+Deno.test("toFixed", () => {
+    assertEquals(toFixed(1.2345), 1.234)
+    assertEquals(toFixed(3.14159, 2), 3.14)
+    assertEquals(toFixed(0.123456789, 6), 0.123457)
+})
+
+Deno.test("clamp", () => {
+    assertEquals(clamp(5, 0, 10), 5)
+    assertEquals(clamp(15, 0, 10), 10)
+    assertEquals(clamp(-5, 0, 10), 0)
+})

lib/svg.js

@@ -1,9 +1,24 @@
 /**
  * Taks a nested array of coordinates and returns a string suitable to pass to
  * the `points` attribute of an SVG polygon element.
- * @param  {...any} coordinates each coordinate is an array like [x, y]
+ * @param  {...any} coordinates an array of coordinates. Each coordinate is an array like [x, y].
  * @returns a string like 'x1,y1 x2,y2 x3,y3'
  */
 export function arrToPolygonPoints(...coordinates) {
-    return coordinates.map(pair => pair.join(',')).join(' ')
+    if (coordinates.length === 0) {
+        throw new Error('Cannot convert empty array to polygon points')
+    }
+
+    return coordinates.map(function (coordinate) {
+        if (!Array.isArray(coordinate)) {
+            throw new Error(`Each coordinate is supposed to be an array. Got ${coodinate}`)
+        }
+        if (coordinate.length !== 2) {
+            throw new Error(`Each coordinate is supposed to be an array of length 2. Got ${coordinate}`)
+        }
+        if (!Number.isFinite(coordinate[0]) || !Number.isFinite(coordinate[1])) {
+            throw new Error(`Each coordinate is supposed to be an array of finite numbers. Got ${coordinate}`)
+        }
+        return coordinate.join(',')
+    }).join(' ')
 }

lib/svg_test.js

@@ -0,0 +1,43 @@
+import { assertEquals, assertThrows } from "https://deno.land/std/testing/asserts.ts"
+import { arrToPolygonPoints } from "./svg.js"
+
+Deno.test("arrToPolygonPoints", () => {
+    const coordinates = [
+        [0, 0],
+        [0, 1],
+        [1, 1],
+        [1, 0],
+    ]
+    const expected = "0,0 0,1 1,1 1,0"
+    assertEquals(arrToPolygonPoints(...coordinates), expected)
+})
+
+Deno.test("arrToPolygonPoints throws with no input", () => {
+    assertThrows(() => arrToPolygonPoints())
+})
+
+Deno.test("arrToPolygonPoints with single point", () => {
+    assertEquals(arrToPolygonPoints(
+        [0, 0]
+    ), '0,0')
+})
+
+Deno.test("arrToPolygonPoints with invalid input", () => {
+    const coordinates = [1, 2, 3]
+    assertThrows(() => arrToPolygonPoints(...coordinates))
+})
+
+Deno.test("arrToPolygonPoints with invalid input", () => {
+    assertThrows(() => arrToPolygonPoints([1, 2, 3]))
+})
+
+Deno.test("arrToPolygonPoints with invalid input", () => {
+    assertThrows(() => arrToPolygonPoints(
+        ["1", 2],
+        [3, 4],
+    ))
+    assertThrows(() => arrToPolygonPoints(
+        [1, 2],
+        [3, "4"],
+    ))
+})

lib/time.js

@@ -1,8 +1,6 @@
 import { toFixed } from "./math.js"
 
-// For a given window unit, what would be the max?
-// The title should be something Intl.RelativeTimeFormat can handle
-// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/RelativeTimeFormat/format
+// Short title matches OpenSLO spec: https://github.com/openslo/openslo#duration-shorthand
 export const windowUnits = [
     {
         title: 'minute',
@@ -78,7 +76,7 @@ export function humanTime(seconds, useShortTitle = false) {
 
     function addToResult(val, { title, shortTitle }) {
         if (useShortTitle) {
-            result.push(`${val} ${shortTitle}`)
+            result.push(`${val}${shortTitle}`)
         } else {
             result.push(`${val} ${title}${val > 1 ? 's' : ''}`)
         }

lib/time_test.js

@@ -0,0 +1,18 @@
+import { assertEquals } from "https://deno.land/std/testing/asserts.ts"
+import { humanTime } from "./time.js"
+
+Deno.test('humanTime()', () => {
+    assertEquals(humanTime(10), '10 seconds')
+    assertEquals(humanTime(60), '1 minute')
+    assertEquals(humanTime(120), '2 minutes')
+    assertEquals(humanTime(3600), '1 hour')
+    assertEquals(humanTime(3660), '1 hour, 1 minute')
+})
+
+Deno.test('humanTime() short form', () => {
+    assertEquals(humanTime(10, true), '10s')
+    assertEquals(humanTime(60, true), '1m')
+    assertEquals(humanTime(120, true), '2m')
+    assertEquals(humanTime(3600, true), '1h')
+    assertEquals(humanTime(3660, true), '1h, 1m')
+})