diff --git a/lib/cli.js b/lib/cli.js
index d4a67645858ae..fbceb459db97c 100644
--- a/lib/cli.js
+++ b/lib/cli.js
@@ -20,6 +20,7 @@ module.exports = (process) => {
 
   const npm = require('../lib/npm.js')
   const errorHandler = require('../lib/utils/error-handler.js')
+  errorHandler.setNpm(npm)
 
   // if npm is called as "npmg" or "npm_g", then
   // run in global mode.
diff --git a/lib/utils/cache-file.js b/lib/utils/cache-file.js
deleted file mode 100644
index b33881e872ec2..0000000000000
--- a/lib/utils/cache-file.js
+++ /dev/null
@@ -1,66 +0,0 @@
-const npm = require('../npm.js')
-const path = require('path')
-const chownr = require('chownr')
-const writeFileAtomic = require('write-file-atomic')
-const mkdirp = require('mkdirp-infer-owner')
-const fs = require('graceful-fs')
-
-let cache = null
-let cacheUid = null
-let cacheGid = null
-let needChown = typeof process.getuid === 'function'
-
-const getCacheOwner = () => {
-  let st
-  try {
-    st = fs.lstatSync(cache)
-  } catch (er) {
-    if (er.code !== 'ENOENT')
-      throw er
-
-    st = fs.lstatSync(path.dirname(cache))
-  }
-
-  cacheUid = st.uid
-  cacheGid = st.gid
-
-  needChown = st.uid !== process.getuid() ||
-    st.gid !== process.getgid()
-}
-
-const writeOrAppend = (method, file, data) => {
-  if (!cache)
-    cache = npm.config.get('cache')
-
-  // redundant if already absolute, but prevents non-absolute files
-  // from being written as if they're part of the cache.
-  file = path.resolve(cache, file)
-
-  if (cacheUid === null && needChown)
-    getCacheOwner()
-
-  const dir = path.dirname(file)
-  const firstMade = mkdirp.sync(dir)
-
-  if (!needChown)
-    return method(file, data)
-
-  let methodThrew = true
-  try {
-    method(file, data)
-    methodThrew = false
-  } finally {
-    // always try to leave it in the right ownership state, even on failure
-    // let the method error fail it instead of the chownr error, though
-    if (!methodThrew)
-      chownr.sync(firstMade || file, cacheUid, cacheGid)
-    else {
-      try {
-        chownr.sync(firstMade || file, cacheUid, cacheGid)
-      } catch (_) {}
-    }
-  }
-}
-
-exports.append = (file, data) => writeOrAppend(fs.appendFileSync, file, data)
-exports.write = (file, data) => writeOrAppend(writeFileAtomic.sync, file, data)
diff --git a/lib/utils/error-handler.js b/lib/utils/error-handler.js
index da716679d2705..f40e1f04fb180 100644
--- a/lib/utils/error-handler.js
+++ b/lib/utils/error-handler.js
@@ -1,28 +1,27 @@
+let npm // set by the cli
 let cbCalled = false
 const log = require('npmlog')
-const npm = require('../npm.js')
 let itWorked = false
 const path = require('path')
+const writeFileAtomic = require('write-file-atomic')
+const mkdirp = require('mkdirp-infer-owner')
+const fs = require('graceful-fs')
 let wroteLogFile = false
 let exitCode = 0
 const errorMessage = require('./error-message.js')
 const replaceInfo = require('./replace-info.js')
 
-const cacheFile = require('./cache-file.js')
-
 let logFileName
 const getLogFile = () => {
+  // we call this multiple times, so we need to treat it as a singleton because
+  // the date is part of the name
   if (!logFileName)
     logFileName = path.resolve(npm.config.get('cache'), '_logs', (new Date()).toISOString().replace(/[.:]/g, '_') + '-debug.log')
 
   return logFileName
 }
 
-const timings = {
-  version: npm.version,
-  command: process.argv.slice(2),
-  logfile: null,
-}
+const timings = {}
 process.on('timing', (name, value) => {
   if (timings[name])
     timings[name] += value
@@ -35,9 +34,21 @@ process.on('exit', code => {
   log.disableProgress()
   if (npm.config && npm.config.loaded && npm.config.get('timing')) {
     try {
-      timings.logfile = getLogFile()
-      cacheFile.append('_timing.json', JSON.stringify(timings) + '\n')
-    } catch (_) {
+      const file = path.resolve(npm.config.get('cache'), '_timing.json')
+      const dir = path.dirname(npm.config.get('cache'))
+      mkdirp.sync(dir)
+
+      fs.appendFileSync(file, JSON.stringify({
+        command: process.argv.slice(2),
+        logfile: getLogFile(),
+        version: npm.version,
+        ...timings,
+      }) + '\n')
+
+      const st = fs.lstatSync(path.dirname(npm.config.get('cache')))
+      fs.chownSync(dir, st.uid, st.gid)
+      fs.chownSync(file, st.uid, st.gid)
+    } catch (ex) {
       // ignore
     }
   }
@@ -174,7 +185,7 @@ const errorHandler = (er) => {
       log.error(k, v)
   }
 
-  const msg = errorMessage(er)
+  const msg = errorMessage(er, npm)
   for (const errline of [...msg.summary, ...msg.detail])
     log.error(...errline)
 
@@ -214,7 +225,15 @@ const writeLogFile = () => {
           logOutput += line + os.EOL
         })
     })
-    cacheFile.write(getLogFile(), logOutput)
+
+    const file = getLogFile()
+    const dir = path.dirname(file)
+    mkdirp.sync(dir)
+    writeFileAtomic.sync(file, logOutput)
+
+    const st = fs.lstatSync(path.dirname(npm.config.get('cache')))
+    fs.chownSync(dir, st.uid, st.gid)
+    fs.chownSync(file, st.uid, st.gid)
 
     // truncate once it's been written.
     log.record.length = 0
@@ -226,3 +245,6 @@ const writeLogFile = () => {
 
 module.exports = errorHandler
 module.exports.exit = exit
+module.exports.setNpm = (n) => {
+  npm = n
+}
diff --git a/lib/utils/error-message.js b/lib/utils/error-message.js
index ac5a935dc8770..125cdf8c53581 100644
--- a/lib/utils/error-message.js
+++ b/lib/utils/error-message.js
@@ -1,12 +1,11 @@
-const npm = require('../npm.js')
 const { format } = require('util')
 const { resolve } = require('path')
 const nameValidator = require('validate-npm-package-name')
 const npmlog = require('npmlog')
 const replaceInfo = require('./replace-info.js')
-const { report: explainEresolve } = require('./explain-eresolve.js')
+const { report } = require('./explain-eresolve.js')
 
-module.exports = (er) => {
+module.exports = (er, npm) => {
   const short = []
   const detail = []
 
@@ -19,7 +18,7 @@ module.exports = (er) => {
     case 'ERESOLVE':
       short.push(['ERESOLVE', er.message])
       detail.push(['', ''])
-      detail.push(['', explainEresolve(er)])
+      detail.push(['', report(er, npm.color, resolve(npm.cache, 'eresolve-report.txt'))])
       break
 
     case 'ENOLOCK': {
diff --git a/lib/utils/explain-eresolve.js b/lib/utils/explain-eresolve.js
index cda77aff94113..b35a32c6f935d 100644
--- a/lib/utils/explain-eresolve.js
+++ b/lib/utils/explain-eresolve.js
@@ -1,20 +1,14 @@
 // this is called when an ERESOLVE error is caught in the error-handler,
 // or when there's a log.warn('eresolve', msg, explanation), to turn it
 // into a human-intelligible explanation of what's wrong and how to fix.
-//
-// TODO: abstract out the explainNode methods into a separate util for
-// use by a future `npm explain <path || spec>` command.
-
-const npm = require('../npm.js')
 const { writeFileSync } = require('fs')
-const { resolve } = require('path')
 const { explainEdge, explainNode, printNode } = require('./explain-dep.js')
 
 // expl is an explanation object that comes from Arborist.  It looks like:
 // Depth is how far we want to want to descend into the object making a report.
 // The full report (ie, depth=Infinity) is always written to the cache folder
 // at ${cache}/eresolve-report.txt along with full json.
-const explainEresolve = (expl, color, depth) => {
+const explain = (expl, color, depth) => {
   const { edge, current, peerConflict, currentEdge } = expl
 
   const out = []
@@ -42,9 +36,7 @@ const explainEresolve = (expl, color, depth) => {
 }
 
 // generate a full verbose report and tell the user how to fix it
-const report = (expl, depth = 4) => {
-  const fullReport = resolve(npm.cache, 'eresolve-report.txt')
-
+const report = (expl, color, fullReport) => {
   const orNoStrict = expl.strictPeerDeps ? '--no-strict-peer-deps, ' : ''
   const fix = `Fix the upstream dependency conflict, or retry
 this command with ${orNoStrict}--force, or --legacy-peer-deps
@@ -54,7 +46,7 @@ to accept an incorrect (and potentially broken) dependency resolution.`
 
 ${new Date().toISOString()}
 
-${explainEresolve(expl, false, Infinity)}
+${explain(expl, false, Infinity)}
 
 ${fix}
 
@@ -63,13 +55,10 @@ Raw JSON explanation object:
 ${JSON.stringify(expl, null, 2)}
 `, 'utf8')
 
-  return explainEresolve(expl, npm.color, depth) +
+  return explain(expl, color, 4) +
     `\n\n${fix}\n\nSee ${fullReport} for a full report.`
 }
 
-// the terser explain method for the warning when using --force
-const explain = (expl, depth = 2) => explainEresolve(expl, npm.color, depth)
-
 module.exports = {
   explain,
   report,
diff --git a/lib/utils/setup-log.js b/lib/utils/setup-log.js
index 44e612d50dc9f..9ee79d192d9ea 100644
--- a/lib/utils/setup-log.js
+++ b/lib/utils/setup-log.js
@@ -14,10 +14,22 @@ module.exports = (config) => {
 
   const { warn } = log
 
+  const stdoutTTY = process.stdout.isTTY
+  const stderrTTY = process.stderr.isTTY
+  const dumbTerm = process.env.TERM === 'dumb'
+  const stderrNotDumb = stderrTTY && !dumbTerm
+  const enableColorStderr = color === 'always' ? true
+    : color === false ? false
+    : stderrTTY
+
+  const enableColorStdout = color === 'always' ? true
+    : color === false ? false
+    : stdoutTTY
+
   log.warn = (heading, ...args) => {
     if (heading === 'ERESOLVE' && args[1] && typeof args[1] === 'object') {
       warn(heading, args[0])
-      return warn('', explain(args[1]))
+      return warn('', explain(args[1], enableColorStdout, 2))
     }
     return warn(heading, ...args)
   }
@@ -29,19 +41,6 @@ module.exports = (config) => {
 
   log.heading = config.get('heading') || 'npm'
 
-  const stdoutTTY = process.stdout.isTTY
-  const stderrTTY = process.stderr.isTTY
-  const dumbTerm = process.env.TERM === 'dumb'
-  const stderrNotDumb = stderrTTY && !dumbTerm
-
-  const enableColorStderr = color === 'always' ? true
-    : color === false ? false
-    : stderrTTY
-
-  const enableColorStdout = color === 'always' ? true
-    : color === false ? false
-    : stdoutTTY
-
   if (enableColorStderr)
     log.enableColor()
   else
diff --git a/tap-snapshots/test/lib/utils/error-handler.js.test.cjs b/tap-snapshots/test/lib/utils/error-handler.js.test.cjs
index 909051cdab506..78a9eef217f35 100644
--- a/tap-snapshots/test/lib/utils/error-handler.js.test.cjs
+++ b/tap-snapshots/test/lib/utils/error-handler.js.test.cjs
@@ -8,7 +8,7 @@
 exports[`test/lib/utils/error-handler.js TAP handles unknown error > should have expected log contents for unknown error 1`] = `
 0 verbose code 1
 1 error foo A complete log of this run can be found in:
-1 error foo     {CWD}/cachefolder/_logs/expecteddate-debug.log
+1 error foo     {CWD}/test/lib/utils/tap-testdir-error-handler/_logs/expecteddate-debug.log
 2 verbose stack Error: ERROR
 3 verbose cwd {CWD}
 4 verbose Foo 1.0.0
diff --git a/tap-snapshots/test/lib/utils/explain-eresolve.js.test.cjs b/tap-snapshots/test/lib/utils/explain-eresolve.js.test.cjs
index e066680153021..4c84aaca4ceeb 100644
--- a/tap-snapshots/test/lib/utils/explain-eresolve.js.test.cjs
+++ b/tap-snapshots/test/lib/utils/explain-eresolve.js.test.cjs
@@ -5,7 +5,7 @@
  * Make sure to inspect the output below.  Do not ignore changes!
  */
 'use strict'
-exports[`test/lib/utils/explain-eresolve.js TAP chain-conflict > explain with color 1`] = `
+exports[`test/lib/utils/explain-eresolve.js TAP chain-conflict > explain with color, depth of 2 1`] = `
 While resolving: project@1.2.3
 Found: @isaacs/testing-peer-dep-conflict-chain-d@2.0.0
 node_modules/@isaacs/testing-peer-dep-conflict-chain-d
@@ -75,25 +75,7 @@ to accept an incorrect (and potentially broken) dependency resolution.
 See \${REPORT} for a full report.
 `
 
-exports[`test/lib/utils/explain-eresolve.js TAP chain-conflict > report with color, depth only 2 1`] = `
-While resolving: project@1.2.3
-Found: @isaacs/testing-peer-dep-conflict-chain-d@2.0.0
-node_modules/@isaacs/testing-peer-dep-conflict-chain-d
-  @isaacs/testing-peer-dep-conflict-chain-d@"2" from the root project
-
-Could not resolve dependency:
-peer @isaacs/testing-peer-dep-conflict-chain-d@"1" from @isaacs/testing-peer-dep-conflict-chain-c@1.0.0
-node_modules/@isaacs/testing-peer-dep-conflict-chain-c
-  @isaacs/testing-peer-dep-conflict-chain-c@"1" from the root project
-
-Fix the upstream dependency conflict, or retry
-this command with --force, or --legacy-peer-deps
-to accept an incorrect (and potentially broken) dependency resolution.
-
-See \${REPORT} for a full report.
-`
-
-exports[`test/lib/utils/explain-eresolve.js TAP chain-conflict > report with no color, depth of 6 1`] = `
+exports[`test/lib/utils/explain-eresolve.js TAP chain-conflict > report with no color 1`] = `
 While resolving: project@1.2.3
 Found: @isaacs/testing-peer-dep-conflict-chain-d@2.0.0
 node_modules/@isaacs/testing-peer-dep-conflict-chain-d
@@ -111,7 +93,7 @@ to accept an incorrect (and potentially broken) dependency resolution.
 See \${REPORT} for a full report.
 `
 
-exports[`test/lib/utils/explain-eresolve.js TAP cycleNested > explain with color 1`] = `
+exports[`test/lib/utils/explain-eresolve.js TAP cycleNested > explain with color, depth of 2 1`] = `
 Found: @isaacs/peer-dep-cycle-c@2.0.0
 node_modules/@isaacs/peer-dep-cycle-c
   @isaacs/peer-dep-cycle-c@"2.x" from the root project
@@ -208,31 +190,7 @@ to accept an incorrect (and potentially broken) dependency resolution.
 See \${REPORT} for a full report.
 `
 
-exports[`test/lib/utils/explain-eresolve.js TAP cycleNested > report with color, depth only 2 1`] = `
-Found: @isaacs/peer-dep-cycle-c@2.0.0
-node_modules/@isaacs/peer-dep-cycle-c
-  @isaacs/peer-dep-cycle-c@"2.x" from the root project
-
-Could not resolve dependency:
-peer @isaacs/peer-dep-cycle-b@"1" from @isaacs/peer-dep-cycle-a@1.0.0
-node_modules/@isaacs/peer-dep-cycle-a
-  @isaacs/peer-dep-cycle-a@"1.x" from the root project
-
-Conflicting peer dependency: @isaacs/peer-dep-cycle-c@1.0.0
-node_modules/@isaacs/peer-dep-cycle-c
-  peer @isaacs/peer-dep-cycle-c@"1" from @isaacs/peer-dep-cycle-b@1.0.0
-  node_modules/@isaacs/peer-dep-cycle-b
-    peer @isaacs/peer-dep-cycle-b@"1" from @isaacs/peer-dep-cycle-a@1.0.0
-    node_modules/@isaacs/peer-dep-cycle-a
-
-Fix the upstream dependency conflict, or retry
-this command with --no-strict-peer-deps, --force, or --legacy-peer-deps
-to accept an incorrect (and potentially broken) dependency resolution.
-
-See \${REPORT} for a full report.
-`
-
-exports[`test/lib/utils/explain-eresolve.js TAP cycleNested > report with no color, depth of 6 1`] = `
+exports[`test/lib/utils/explain-eresolve.js TAP cycleNested > report with no color 1`] = `
 Found: @isaacs/peer-dep-cycle-c@2.0.0
 node_modules/@isaacs/peer-dep-cycle-c
   @isaacs/peer-dep-cycle-c@"2.x" from the root project
@@ -257,7 +215,7 @@ to accept an incorrect (and potentially broken) dependency resolution.
 See \${REPORT} for a full report.
 `
 
-exports[`test/lib/utils/explain-eresolve.js TAP gatsby > explain with color 1`] = `
+exports[`test/lib/utils/explain-eresolve.js TAP gatsby > explain with color, depth of 2 1`] = `
 While resolving: gatsby-recipes@0.2.31
 Found: ink@3.0.0-7
 node_modules/ink
@@ -366,29 +324,7 @@ to accept an incorrect (and potentially broken) dependency resolution.
 See \${REPORT} for a full report.
 `
 
-exports[`test/lib/utils/explain-eresolve.js TAP gatsby > report with color, depth only 2 1`] = `
-While resolving: gatsby-recipes@0.2.31
-Found: ink@3.0.0-7
-node_modules/ink
-  dev ink@"next" from gatsby-recipes@0.2.31
-  node_modules/gatsby-recipes
-    gatsby-recipes@"^0.2.31" from gatsby-cli@2.12.107
-    node_modules/gatsby-cli
-
-Could not resolve dependency:
-peer ink@">=2.0.0" from ink-box@1.0.0
-node_modules/ink-box
-  ink-box@"^1.0.0" from gatsby-recipes@0.2.31
-  node_modules/gatsby-recipes
-
-Fix the upstream dependency conflict, or retry
-this command with --no-strict-peer-deps, --force, or --legacy-peer-deps
-to accept an incorrect (and potentially broken) dependency resolution.
-
-See \${REPORT} for a full report.
-`
-
-exports[`test/lib/utils/explain-eresolve.js TAP gatsby > report with no color, depth of 6 1`] = `
+exports[`test/lib/utils/explain-eresolve.js TAP gatsby > report with no color 1`] = `
 While resolving: gatsby-recipes@0.2.31
 Found: ink@3.0.0-7
 node_modules/ink
@@ -409,7 +345,6 @@ node_modules/ink-box
     node_modules/gatsby-cli
       gatsby-cli@"^2.12.107" from gatsby@2.24.74
       node_modules/gatsby
-        gatsby@"" from the root project
 
 Fix the upstream dependency conflict, or retry
 this command with --no-strict-peer-deps, --force, or --legacy-peer-deps
@@ -418,7 +353,7 @@ to accept an incorrect (and potentially broken) dependency resolution.
 See \${REPORT} for a full report.
 `
 
-exports[`test/lib/utils/explain-eresolve.js TAP no current node, but has current edge > explain with color 1`] = `
+exports[`test/lib/utils/explain-eresolve.js TAP no current node, but has current edge > explain with color, depth of 2 1`] = `
 While resolving: eslint@7.22.0
 Found: dev eslint@"file:." from the root project
 
@@ -480,23 +415,7 @@ to accept an incorrect (and potentially broken) dependency resolution.
 See \${REPORT} for a full report.
 `
 
-exports[`test/lib/utils/explain-eresolve.js TAP no current node, but has current edge > report with color, depth only 2 1`] = `
-While resolving: eslint@7.22.0
-Found: dev eslint@"file:." from the root project
-
-Could not resolve dependency:
-peer eslint@"^6.0.0" from eslint-plugin-jsdoc@22.2.0
-node_modules/eslint-plugin-jsdoc
-  dev eslint-plugin-jsdoc@"^22.1.0" from the root project
-
-Fix the upstream dependency conflict, or retry
-this command with --force, or --legacy-peer-deps
-to accept an incorrect (and potentially broken) dependency resolution.
-
-See \${REPORT} for a full report.
-`
-
-exports[`test/lib/utils/explain-eresolve.js TAP no current node, but has current edge > report with no color, depth of 6 1`] = `
+exports[`test/lib/utils/explain-eresolve.js TAP no current node, but has current edge > report with no color 1`] = `
 While resolving: eslint@7.22.0
 Found: dev eslint@"file:." from the root project
 
@@ -512,7 +431,7 @@ to accept an incorrect (and potentially broken) dependency resolution.
 See \${REPORT} for a full report.
 `
 
-exports[`test/lib/utils/explain-eresolve.js TAP no current node, no current edge, idk > explain with color 1`] = `
+exports[`test/lib/utils/explain-eresolve.js TAP no current node, no current edge, idk > explain with color, depth of 2 1`] = `
 While resolving: eslint@7.22.0
 
 Could not resolve dependency:
@@ -570,22 +489,7 @@ to accept an incorrect (and potentially broken) dependency resolution.
 See \${REPORT} for a full report.
 `
 
-exports[`test/lib/utils/explain-eresolve.js TAP no current node, no current edge, idk > report with color, depth only 2 1`] = `
-While resolving: eslint@7.22.0
-
-Could not resolve dependency:
-peer eslint@"^6.0.0" from eslint-plugin-jsdoc@22.2.0
-node_modules/eslint-plugin-jsdoc
-  dev eslint-plugin-jsdoc@"^22.1.0" from the root project
-
-Fix the upstream dependency conflict, or retry
-this command with --force, or --legacy-peer-deps
-to accept an incorrect (and potentially broken) dependency resolution.
-
-See \${REPORT} for a full report.
-`
-
-exports[`test/lib/utils/explain-eresolve.js TAP no current node, no current edge, idk > report with no color, depth of 6 1`] = `
+exports[`test/lib/utils/explain-eresolve.js TAP no current node, no current edge, idk > report with no color 1`] = `
 While resolving: eslint@7.22.0
 
 Could not resolve dependency:
@@ -600,7 +504,7 @@ to accept an incorrect (and potentially broken) dependency resolution.
 See \${REPORT} for a full report.
 `
 
-exports[`test/lib/utils/explain-eresolve.js TAP withShrinkwrap > explain with color 1`] = `
+exports[`test/lib/utils/explain-eresolve.js TAP withShrinkwrap > explain with color, depth of 2 1`] = `
 While resolving: @isaacs/peer-dep-cycle-b@1.0.0
 Found: @isaacs/peer-dep-cycle-c@2.0.0
 node_modules/@isaacs/peer-dep-cycle-c
@@ -677,26 +581,7 @@ to accept an incorrect (and potentially broken) dependency resolution.
 See \${REPORT} for a full report.
 `
 
-exports[`test/lib/utils/explain-eresolve.js TAP withShrinkwrap > report with color, depth only 2 1`] = `
-While resolving: @isaacs/peer-dep-cycle-b@1.0.0
-Found: @isaacs/peer-dep-cycle-c@2.0.0
-node_modules/@isaacs/peer-dep-cycle-c
-  @isaacs/peer-dep-cycle-c@"2.x" from the root project
-
-Could not resolve dependency:
-peer @isaacs/peer-dep-cycle-c@"1" from @isaacs/peer-dep-cycle-b@1.0.0
-node_modules/@isaacs/peer-dep-cycle-b
-  peer @isaacs/peer-dep-cycle-b@"1" from @isaacs/peer-dep-cycle-a@1.0.0
-  node_modules/@isaacs/peer-dep-cycle-a
-
-Fix the upstream dependency conflict, or retry
-this command with --no-strict-peer-deps, --force, or --legacy-peer-deps
-to accept an incorrect (and potentially broken) dependency resolution.
-
-See \${REPORT} for a full report.
-`
-
-exports[`test/lib/utils/explain-eresolve.js TAP withShrinkwrap > report with no color, depth of 6 1`] = `
+exports[`test/lib/utils/explain-eresolve.js TAP withShrinkwrap > report with no color 1`] = `
 While resolving: @isaacs/peer-dep-cycle-b@1.0.0
 Found: @isaacs/peer-dep-cycle-c@2.0.0
 node_modules/@isaacs/peer-dep-cycle-c
diff --git a/test/lib/cli.js b/test/lib/cli.js
index 42e05cc5d14c3..d0a9e0bd49200 100644
--- a/test/lib/cli.js
+++ b/test/lib/cli.js
@@ -25,6 +25,7 @@ const unsupportedMock = {
 }
 
 let errorHandlerCalled = null
+let errorHandlerNpm = null
 let errorHandlerCb
 const errorHandlerMock = (...args) => {
   errorHandlerCalled = args
@@ -35,6 +36,9 @@ let errorHandlerExitCalled = null
 errorHandlerMock.exit = code => {
   errorHandlerExitCalled = code
 }
+errorHandlerMock.setNpm = npm => {
+  errorHandlerNpm = npm
+}
 
 const logs = []
 const npmlogMock = {
@@ -181,6 +185,7 @@ t.test('gracefully handles error printing usage', t => {
   npmock.argv = []
   errorHandlerCb = () => {
     t.match(errorHandlerCalled, [], 'should call errorHandler with no args')
+    t.match(errorHandlerNpm, npmock, 'errorHandler npm is set')
     t.end()
   }
   cli(proc)
diff --git a/test/lib/load-all.js b/test/lib/load-all.js
index 02736c18ccc38..4a975d49a490e 100644
--- a/test/lib/load-all.js
+++ b/test/lib/load-all.js
@@ -24,6 +24,7 @@ else {
 
   t.test('call the error handle so we dont freak out', t => {
     const errorHandler = require('../../lib/utils/error-handler.js')
+    errorHandler.setNpm(npm)
     errorHandler()
     t.end()
   })
diff --git a/test/lib/utils/error-handler.js b/test/lib/utils/error-handler.js
index a00bac76e11c2..9a681e52ce5db 100644
--- a/test/lib/utils/error-handler.js
+++ b/test/lib/utils/error-handler.js
@@ -1,6 +1,7 @@
 /* eslint-disable no-extend-native */
 /* eslint-disable no-global-assign */
 const EventEmitter = require('events')
+const writeFileAtomic = require('write-file-atomic')
 const t = require('tap')
 
 // NOTE: Although these unit tests may look like the rest on the surface,
@@ -23,13 +24,10 @@ const redactCwd = (path) => {
 t.cleanSnapshot = (str) => redactCwd(str)
 
 // internal modules mocks
-const cacheFile = {
-  append: () => null,
-  write: () => null,
-}
+const cacheFolder = t.testdir({})
 const config = {
   values: {
-    cache: 'cachefolder',
+    cache: cacheFolder,
     timing: true,
   },
   loaded: true,
@@ -111,20 +109,20 @@ process = Object.assign(
 // in order for tap to exit properly
 t.teardown(() => {
   process = _process
+  npmlog.record.length = 0
 })
 
 const mocks = {
   npmlog,
-  '../../../lib/npm.js': npm,
   '../../../lib/utils/error-message.js': (err) => ({
     ...err,
     summary: [['ERR', err.message]],
     detail: [['ERR', err.message]],
   }),
-  '../../../lib/utils/cache-file.js': cacheFile,
 }
 
 let errorHandler = t.mock('../../../lib/utils/error-handler.js', mocks)
+errorHandler.setNpm(npm)
 
 t.test('default exit code', (t) => {
   t.plan(1)
@@ -160,10 +158,14 @@ t.test('default exit code', (t) => {
 t.test('handles unknown error', (t) => {
   t.plan(2)
 
-  cacheFile.write = (filename, content) => {
+  const _toISOString = Date.prototype.toISOString
+  Date.prototype.toISOString = () => 'expecteddate'
+
+  const sync = writeFileAtomic.sync
+  writeFileAtomic.sync = (filename, content) => {
     t.equal(
       redactCwd(filename),
-      '{CWD}/cachefolder/_logs/expecteddate-debug.log',
+      '{CWD}/test/lib/utils/tap-testdir-error-handler/_logs/expecteddate-debug.log',
       'should use expected log filename'
     )
     t.matchSnapshot(
@@ -175,7 +177,8 @@ t.test('handles unknown error', (t) => {
   errorHandler(err)
 
   t.teardown(() => {
-    cacheFile.write = () => null
+    writeFileAtomic.sync = sync
+    Date.prototype.toISOString = _toISOString
   })
   t.end()
 })
@@ -205,11 +208,14 @@ t.test('npm.config not ready', (t) => {
 t.test('fail to write logfile', (t) => {
   t.plan(1)
 
-  cacheFile.write = () => {
-    throw err
-  }
+  const badDir = t.testdir({
+    _logs: 'is a file',
+  })
+
+  config.values.cache = badDir
+
   t.teardown(() => {
-    cacheFile.write = () => null
+    config.values.cache = cacheFolder
   })
 
   t.doesNotThrow(
@@ -372,6 +378,7 @@ t.test('uses code from errno', (t) => {
   t.plan(1)
 
   errorHandler = t.mock('../../../lib/utils/error-handler.js', mocks)
+  errorHandler.setNpm(npm)
 
   npmlog.level = 'silent'
   const _exit = process.exit
@@ -396,6 +403,7 @@ t.test('uses exitCode as code if using a number', (t) => {
   t.plan(1)
 
   errorHandler = t.mock('../../../lib/utils/error-handler.js', mocks)
+  errorHandler.setNpm(npm)
 
   npmlog.level = 'silent'
   const _exit = process.exit
@@ -420,6 +428,7 @@ t.test('call errorHandler with no error', (t) => {
   t.plan(1)
 
   errorHandler = t.mock('../../../lib/utils/error-handler.js', mocks)
+  errorHandler.setNpm(npm)
 
   const _exit = process.exit
   process.exit = (code) => {
@@ -478,6 +487,7 @@ t.test('set it worked', (t) => {
   t.plan(1)
 
   errorHandler = t.mock('../../../lib/utils/error-handler.js', mocks)
+  errorHandler.setNpm(npm)
 
   const _exit = process.exit
   process.exit = () => {
diff --git a/test/lib/utils/error-message.js b/test/lib/utils/error-message.js
index 7529aac2d4a4b..4f94645a4542d 100644
--- a/test/lib/utils/error-message.js
+++ b/test/lib/utils/error-message.js
@@ -1,4 +1,5 @@
 const t = require('tap')
+const path = require('path')
 
 // make a bunch of stuff consistent for snapshots
 
@@ -48,7 +49,7 @@ const mocks = {
       return 'explanation'
     },
   },
-  '../../../lib/npm.js': require('../../../lib/npm.js'),
+  // XXX ???
   get '../../../lib/utils/is-windows.js' () {
     return process.platform === 'win32'
   },
@@ -110,7 +111,7 @@ t.test('just simple messages', t => {
       file,
       stack,
     })
-    t.matchSnapshot(errorMessage(er))
+    t.matchSnapshot(errorMessage(er, npm))
   })
 })
 
@@ -128,7 +129,7 @@ t.test('replace message/stack sensistive info', t => {
     file,
     stack,
   })
-  t.matchSnapshot(errorMessage(er))
+  t.matchSnapshot(errorMessage(er, npm))
   t.end()
 })
 
@@ -148,7 +149,7 @@ t.test('bad engine with config loaded', t => {
     file,
     stack,
   })
-  t.matchSnapshot(errorMessage(er))
+  t.matchSnapshot(errorMessage(er, npm))
   t.end()
 })
 
@@ -162,7 +163,7 @@ t.test('enoent without a file', t => {
     pkgid,
     stack,
   })
-  t.matchSnapshot(errorMessage(er))
+  t.matchSnapshot(errorMessage(er, npm))
   t.end()
 })
 
@@ -179,20 +180,20 @@ t.test('enolock without a command', t => {
     file,
     stack,
   })
-  t.matchSnapshot(errorMessage(er))
+  t.matchSnapshot(errorMessage(er, npm))
   t.end()
 })
 
 t.test('default message', t => {
-  t.matchSnapshot(errorMessage(new Error('error object')))
-  t.matchSnapshot(errorMessage('error string'))
+  t.matchSnapshot(errorMessage(new Error('error object'), npm))
+  t.matchSnapshot(errorMessage('error string'), npm)
   t.matchSnapshot(errorMessage(Object.assign(new Error('cmd err'), {
     cmd: 'some command',
     signal: 'SIGYOLO',
     args: ['a', 'r', 'g', 's'],
     stdout: 'stdout',
     stderr: 'stderr',
-  })))
+  }), npm))
   t.end()
 })
 
@@ -213,7 +214,7 @@ t.test('eacces/eperm', t => {
       stack: 'dummy stack trace',
     })
     verboseLogs.length = 0
-    t.matchSnapshot(errorMessage(er))
+    t.matchSnapshot(errorMessage(er, npm))
     t.matchSnapshot(verboseLogs)
     t.end()
     verboseLogs.length = 0
@@ -288,7 +289,7 @@ t.test('json parse', t => {
     t.matchSnapshot(errorMessage(Object.assign(new Error('conflicted'), {
       code: 'EJSONPARSE',
       file: resolve(dir, 'package.json'),
-    })))
+    }), npm))
     t.end()
   })
 
@@ -310,7 +311,7 @@ t.test('json parse', t => {
     t.matchSnapshot(errorMessage(Object.assign(new Error('not json'), {
       code: 'EJSONPARSE',
       file: resolve(dir, 'package.json'),
-    })))
+    }), npm))
     t.end()
   })
 
@@ -326,7 +327,7 @@ t.test('json parse', t => {
     t.matchSnapshot(errorMessage(Object.assign(new Error('not json'), {
       code: 'EJSONPARSE',
       file: `${dir}/blerg.json`,
-    })))
+    }), npm))
     t.end()
   })
 
@@ -337,21 +338,21 @@ t.test('eotp/e401', t => {
   t.test('401, no auth headers', t => {
     t.matchSnapshot(errorMessage(Object.assign(new Error('nope'), {
       code: 'E401',
-    })))
+    }), npm))
     t.end()
   })
 
   t.test('401, no message', t => {
     t.matchSnapshot(errorMessage({
       code: 'E401',
-    }))
+    }, npm))
     t.end()
   })
 
   t.test('one-time pass challenge code', t => {
     t.matchSnapshot(errorMessage(Object.assign(new Error('nope'), {
       code: 'EOTP',
-    })))
+    }), npm))
     t.end()
   })
 
@@ -359,7 +360,7 @@ t.test('eotp/e401', t => {
     const message = 'one-time pass'
     t.matchSnapshot(errorMessage(Object.assign(new Error(message), {
       code: 'E401',
-    })))
+    }), npm))
     t.end()
   })
 
@@ -379,7 +380,7 @@ t.test('eotp/e401', t => {
           },
           code: 'E401',
         })
-        t.matchSnapshot(errorMessage(er))
+        t.matchSnapshot(errorMessage(er, npm))
         t.end()
       })
     }
@@ -391,7 +392,7 @@ t.test('eotp/e401', t => {
 t.test('404', t => {
   t.test('no package id', t => {
     const er = Object.assign(new Error('404 not found'), { code: 'E404' })
-    t.matchSnapshot(errorMessage(er))
+    t.matchSnapshot(errorMessage(er, npm))
     t.end()
   })
   t.test('you should publish it', t => {
@@ -399,7 +400,7 @@ t.test('404', t => {
       pkgid: 'yolo',
       code: 'E404',
     })
-    t.matchSnapshot(errorMessage(er))
+    t.matchSnapshot(errorMessage(er, npm))
     t.end()
   })
   t.test('name with warning', t => {
@@ -407,7 +408,7 @@ t.test('404', t => {
       pkgid: new Array(215).fill('x').join(''),
       code: 'E404',
     })
-    t.matchSnapshot(errorMessage(er))
+    t.matchSnapshot(errorMessage(er, npm))
     t.end()
   })
   t.test('name with error', t => {
@@ -415,7 +416,7 @@ t.test('404', t => {
       pkgid: 'node_modules',
       code: 'E404',
     })
-    t.matchSnapshot(errorMessage(er))
+    t.matchSnapshot(errorMessage(er, npm))
     t.end()
   })
   t.end()
@@ -435,7 +436,7 @@ t.test('bad platform', t => {
       },
       code: 'EBADPLATFORM',
     })
-    t.matchSnapshot(errorMessage(er))
+    t.matchSnapshot(errorMessage(er, npm))
     t.end()
   })
   t.test('array os/arch', t => {
@@ -451,7 +452,7 @@ t.test('bad platform', t => {
       },
       code: 'EBADPLATFORM',
     })
-    t.matchSnapshot(errorMessage(er))
+    t.matchSnapshot(errorMessage(er, npm))
     t.end()
   })
 
@@ -462,7 +463,11 @@ t.test('explain ERESOLVE errors', t => {
   const er = Object.assign(new Error('could not resolve'), {
     code: 'ERESOLVE',
   })
-  t.matchSnapshot(errorMessage(er))
-  t.strictSame(EXPLAIN_CALLED, [[er]])
+  t.matchSnapshot(errorMessage(er, npm))
+  t.match(EXPLAIN_CALLED, [[
+    er,
+    undefined,
+    path.resolve(npm.cache, 'eresolve-report.txt'),
+  ]])
   t.end()
 })
diff --git a/test/lib/utils/explain-eresolve.js b/test/lib/utils/explain-eresolve.js
index 90795bb4470b2..f9710ee889ab1 100644
--- a/test/lib/utils/explain-eresolve.js
+++ b/test/lib/utils/explain-eresolve.js
@@ -1,8 +1,6 @@
 const t = require('tap')
 const npm = {}
-const { explain, report } = t.mock('../../../lib/utils/explain-eresolve.js', {
-  '../../../lib/npm.js': npm,
-})
+const { explain, report } = require('../../../lib/utils/explain-eresolve.js')
 const { statSync, readFileSync, unlinkSync } = require('fs')
 // strip out timestamps from reports
 const read = f => readFileSync(f, 'utf8')
@@ -25,23 +23,18 @@ for (const [name, expl] of Object.entries(cases)) {
     t.cleanSnapshot = str => str.split(reportFile).join('${REPORT}')
 
     npm.color = true
-    t.matchSnapshot(report(expl), 'report with color')
+    t.matchSnapshot(report(expl, true, reportFile), 'report with color')
     const reportData = read(reportFile)
     t.matchSnapshot(reportData, 'report')
     unlinkSync(reportFile)
-    t.matchSnapshot(report(expl, 2), 'report with color, depth only 2')
+
+    t.matchSnapshot(report(expl, false, reportFile), 'report with no color')
     t.equal(read(reportFile), reportData, 'same report written for object')
     unlinkSync(reportFile)
-    npm.color = false
-    t.matchSnapshot(report(expl, 6), 'report with no color, depth of 6')
-    t.equal(read(reportFile), reportData, 'same report written for object')
 
-    unlinkSync(reportFile)
-    npm.color = true
-    t.matchSnapshot(explain(expl), 'explain with color')
+    t.matchSnapshot(explain(expl, true, 2), 'explain with color, depth of 2')
     t.throws(() => statSync(reportFile), { code: 'ENOENT' }, 'no report')
-    npm.color = false
-    t.matchSnapshot(explain(expl, 6), 'explain with no color, depth of 6')
+    t.matchSnapshot(explain(expl, false, 6), 'explain with no color, depth of 6')
     t.throws(() => statSync(reportFile), { code: 'ENOENT' }, 'no report')
 
     t.end()
diff --git a/test/lib/utils/setup-log.js b/test/lib/utils/setup-log.js
index 3daf3b8a52f53..86befe6e29297 100644
--- a/test/lib/utils/setup-log.js
+++ b/test/lib/utils/setup-log.js
@@ -92,7 +92,7 @@ t.test('setup with color=always and unicode', t => {
   })), true)
 
   npmlog.warn('ERESOLVE', 'hello', { some: { other: 'object' } })
-  t.strictSame(EXPLAIN_CALLED, [[{ some: { other: 'object' } }]],
+  t.strictSame(EXPLAIN_CALLED, [[{ some: { other: 'object' } }, true, 2]],
     'log.warn(ERESOLVE) patched to call explainEresolve()')
   t.strictSame(WARN_CALLED, [
     ['ERESOLVE', 'hello'],