(ml5717) Added unit tests for interval spread and flatten

__tests__/erasure.test.js

 import {
   computeErasureIntervals,
   combineErasureIntervals,
+  spreadErasureIntervals,
+  flattenErasureIntervals,
 } from "../src/erasure.js"
 
 describe("erasure intervals", () => {
@@ -91,4 +93,31 @@ describe("erasure intervals", () => {
 
     expect(combined).toStrictEqual(expected)
   })
+
+  it("spreads flattened intervals", () => {
+    const il = [[0.1, 1.25], [1.5, 2.0], [7.5, 7.75]]
+
+    const spread = spreadErasureIntervals(il)
+    const expected = { 0: [[0.1, 1.0]], 1: [[0.0, 0.25], [0.5, 1.0]], 7: [[0.5, 0.75]] }
+
+    expect(spread).toStrictEqual(expected)
+  })
+
+  it("spreads singulatity intervals", () => {
+    const il = [[0.0, 0.0], [3.5, 3.5], [99.0, 99.0]]
+
+    const spread = spreadErasureIntervals(il)
+    const expected = { 0: [[0.0, 0.0]], 3: [[0.5, 0.5]], 99: [[0.0, 0.0]] }
+
+    expect(spread).toStrictEqual(expected)
+  })
+
+  it("flattens spread intervals", () => {
+    const is = { 0: [[0.1, 1.0]], 1: [[0.0, 0.3], [0.4, 1.0]], 7: [[0.35, 0.75]] }
+
+    const flattened = flattenErasureIntervals(is)
+    const expected = [[0.1, 1.0], [1.0, 1.3], [1.4, 2.0], [7.35, 7.75]]
+
+    expect(flattened).toStrictEqual(expected)
+  })
 })

src/erasure.js

@@ -127,7 +127,7 @@ export function combineErasureIntervals(i1, i2) {
 }
 
 export function spreadErasureIntervals(intervals) {
-  const spread = []
+  const spread = {}
 
   intervals.forEach(([l, u]) => {
     if (u > l) {