test: use more precise time comparison (#5268)

* test: use more precise time comparison

This approach covers the edge case
when 2 numeric values are in the same precision vicinity,
but get rounded to the different values.

E.g. `a = 0.514` and `b = 0.516`.
The diff is `0.002`,
but the diff between rounded values was `0.01` before this fix.

This is a tiny fix, but without it, the CI fails from time to time.
That could cost ~35m of waiting time in the merge queue.

* chore: sorted imports

core/src/util/testing.ts

@@ -8,7 +8,7 @@
 
 import { GlobalOptions, globalOptions, ParameterValues } from "../cli/params"
 import cloneDeep from "fast-copy"
-import { isEqual, keyBy, set, mapValues } from "lodash"
+import { isEqual, keyBy, set, mapValues, round } from "lodash"
 import { Garden, GardenOpts, GardenParams, GetConfigGraphParams, resolveGardenParams } from "../garden"
 import { DeepPrimitiveMap, StringMap } from "../config/common"
 import { ModuleConfig } from "../config/module"
@@ -534,3 +534,10 @@ export function captureStream(stream: NodeJS.WritableStream) {
     },
   }
 }
+
+export function equalWithPrecision(a: number, b: number, precision: number): boolean {
+  const rawDiff = Math.abs(a - b)
+  const diff = round(rawDiff, precision)
+  const eps = Math.pow(10, -precision)
+  return diff <= eps
+}

core/test/unit/src/build-staging/helpers.ts

@@ -8,19 +8,20 @@
 
 import { join } from "path"
 import {
-  FileStatsHelper,
+  cloneFileAsync,
   ExtendedStats,
+  FileStatsHelper,
+  MappedPaths,
   ResolveSymlinkParams,
-  cloneFileAsync,
   scanDirectoryForClone,
-  MappedPaths,
 } from "../../../../src/build-staging/helpers"
-import { TempDirectory, makeTempDir } from "../../../../src/util/fs"
-import { realpath, symlink, writeFile, readFile, mkdir, ensureFile, ensureDir } from "fs-extra"
+import { makeTempDir, TempDirectory } from "../../../../src/util/fs"
+import { ensureDir, ensureFile, mkdir, readFile, realpath, symlink, writeFile } from "fs-extra"
 import { expect } from "chai"
 import { expectError } from "../../../helpers"
 import { sleep } from "../../../../src/util/util"
-import { round, sortBy } from "lodash"
+import { sortBy } from "lodash"
+import { equalWithPrecision } from "../../../../src/util/testing"
 
 describe("build staging helpers", () => {
   let statsHelper: FileStatsHelper
@@ -86,7 +87,7 @@ describe("build staging helpers", () => {
       const statA = await statsHelper.extendedStat({ path: a })
       const statB = await statsHelper.extendedStat({ path: b })
 
-      expect(round(statA?.mtimeMs!, 2)).to.equal(round(statB?.mtimeMs!, 2))
+      expect(equalWithPrecision(statA?.mtimeMs!, statB?.mtimeMs!, 2)).to.be.true
     })
 
     it("skips if file at target exists and has same mtime and size", async () => {