diff --git a/.eslintrc.js b/.eslintrc.js
index d9c68e8b0..28c478560 100644
--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -124,6 +124,7 @@ module.exports = {
 
     "unicorn/better-regex": "error",
     "unicorn/explicit-length-check": "error",
+    "unicorn/filename-case": "error",
     "unicorn/new-for-builtins": "error",
     "unicorn/no-array-for-each": "error",
     "unicorn/no-array-push-push": "error",
@@ -289,6 +290,7 @@ module.exports = {
         "react/display-name": "off",
         "react/no-deprecated": "off",
         "react/prop-types": "off",
+        "unicorn/filename-case": "off",
       },
     },
     {
diff --git a/src/language-css/parser-postcss.js b/src/language-css/parser-postcss.js
index 5f60fac95..ac334014d 100644
--- a/src/language-css/parser-postcss.js
+++ b/src/language-css/parser-postcss.js
@@ -6,12 +6,12 @@ const parseFrontMatter = require("../utils/front-matter/parse.js");
 const { hasPragma } = require("./pragma.js");
 const { locStart, locEnd } = require("./loc.js");
 const { calculateLoc, replaceQuotesInInlineComments } = require("./loc.js");
-const hasSCSSInterpolation = require("./utils/has-SCSS-interpolation.js");
+const hasSCSSInterpolation = require("./utils/has-scss-interpolation.js");
 const hasStringOrFunction = require("./utils/has-string-or-function.js");
 const isLessParser = require("./utils/is-less-parser.js");
 const isSCSS = require("./utils/is-scss.js");
-const isSCSSNestedPropertyNode = require("./utils/is-SCSS-nested-property-node.js");
-const isSCSSVariable = require("./utils/is-SCSS-variable.js");
+const isSCSSNestedPropertyNode = require("./utils/is-scss-nested-property-node.js");
+const isSCSSVariable = require("./utils/is-scss-variable.js");
 const stringifyNode = require("./utils/stringify-node.js");
 const isModuleRuleName = require("./utils/is-module-rule-name.js");
 
diff --git a/src/language-css/utils/has-SCSS-interpolation.js b/src/language-css/utils/has-scss-interpolation.js
similarity index 100%
rename from src/language-css/utils/has-SCSS-interpolation.js
rename to src/language-css/utils/has-scss-interpolation.js
diff --git a/src/language-css/utils/is-SCSS-nested-property-node.js b/src/language-css/utils/is-scss-nested-property-node.js
similarity index 100%
rename from src/language-css/utils/is-SCSS-nested-property-node.js
rename to src/language-css/utils/is-scss-nested-property-node.js
diff --git a/src/language-css/utils/is-SCSS-variable.js b/src/language-css/utils/is-scss-variable.js
similarity index 100%
rename from src/language-css/utils/is-SCSS-variable.js
rename to src/language-css/utils/is-scss-variable.js
diff --git a/src/language-js/parse/postprocess/index.js b/src/language-js/parse/postprocess/index.js
index cbd197dc8..3b3260bc6 100644
--- a/src/language-js/parse/postprocess/index.js
+++ b/src/language-js/parse/postprocess/index.js
@@ -4,7 +4,7 @@ const { locStart, locEnd } = require("../../loc.js");
 const isTsKeywordType = require("../../utils/is-ts-keyword-type.js");
 const isTypeCastComment = require("../../utils/is-type-cast-comment.js");
 const getLast = require("../../../utils/get-last.js");
-const visitNode = require("./visitNode.js");
+const visitNode = require("./visit-node.js");
 const { throwErrorForInvalidNodes } = require("./typescript.js");
 
 function postprocess(ast, options) {
diff --git a/src/language-js/parse/postprocess/typescript.js b/src/language-js/parse/postprocess/typescript.js
index 329280a70..39a71708f 100644
--- a/src/language-js/parse/postprocess/typescript.js
+++ b/src/language-js/parse/postprocess/typescript.js
@@ -1,7 +1,7 @@
 "use strict";
 
 const createError = require("../../../common/parser-create-error.js");
-const visitNode = require("./visitNode.js");
+const visitNode = require("./visit-node.js");
 
 function throwSyntaxError(node, message) {
   const { start, end } = node.loc;
diff --git a/src/language-js/parse/postprocess/visitNode.js b/src/language-js/parse/postprocess/visit-node.js
similarity index 100%
rename from src/language-js/parse/postprocess/visitNode.js
rename to src/language-js/parse/postprocess/visit-node.js
diff --git a/tests/integration/__tests__/arg-parsing.js b/tests/integration/__tests__/arg-parsing.js
index d04a45f24..433def782 100644
--- a/tests/integration/__tests__/arg-parsing.js
+++ b/tests/integration/__tests__/arg-parsing.js
@@ -1,6 +1,6 @@
 "use strict";
 
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 expect.addSnapshotSerializer(require("../path-serializer.js"));
 
 describe("boolean flags do not swallow the next argument", () => {
diff --git a/tests/integration/__tests__/check.js b/tests/integration/__tests__/check.js
index e47eec277..76b4acab5 100644
--- a/tests/integration/__tests__/check.js
+++ b/tests/integration/__tests__/check.js
@@ -1,6 +1,6 @@
 "use strict";
 
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 
 describe("checks stdin with --check", () => {
   runPrettier("cli/with-shebang", ["--check", "--parser", "babel"], {
diff --git a/tests/integration/__tests__/config-invalid.js b/tests/integration/__tests__/config-invalid.js
index d8acde855..c27902982 100644
--- a/tests/integration/__tests__/config-invalid.js
+++ b/tests/integration/__tests__/config-invalid.js
@@ -1,6 +1,6 @@
 "use strict";
 
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 
 expect.addSnapshotSerializer(require("../path-serializer.js"));
 
diff --git a/tests/integration/__tests__/config-resolution.js b/tests/integration/__tests__/config-resolution.js
index 7e39b7f8f..84149e970 100644
--- a/tests/integration/__tests__/config-resolution.js
+++ b/tests/integration/__tests__/config-resolution.js
@@ -3,7 +3,7 @@
 const path = require("path");
 
 const prettier = require("prettier-local");
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 
 expect.addSnapshotSerializer(require("../path-serializer.js"));
 
diff --git a/tests/integration/__tests__/cursor-offset.js b/tests/integration/__tests__/cursor-offset.js
index e8c4f375b..38f8fc7eb 100644
--- a/tests/integration/__tests__/cursor-offset.js
+++ b/tests/integration/__tests__/cursor-offset.js
@@ -1,6 +1,6 @@
 "use strict";
 
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 
 describe("write cursorOffset to stderr with --cursor-offset <int>", () => {
   runPrettier("cli", ["--cursor-offset", "2", "--parser", "babel"], {
diff --git a/tests/integration/__tests__/debug-check.js b/tests/integration/__tests__/debug-check.js
index 94a196d5f..bd96aa85c 100644
--- a/tests/integration/__tests__/debug-check.js
+++ b/tests/integration/__tests__/debug-check.js
@@ -1,6 +1,6 @@
 "use strict";
 
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 
 describe("doesn't crash when --debug-check is passed", () => {
   runPrettier("cli/with-shebang", ["issue1890.js", "--debug-check"]).test({
diff --git a/tests/integration/__tests__/debug-print-ast.js b/tests/integration/__tests__/debug-print-ast.js
index 53022674e..7927bff34 100644
--- a/tests/integration/__tests__/debug-print-ast.js
+++ b/tests/integration/__tests__/debug-print-ast.js
@@ -1,6 +1,6 @@
 "use strict";
 
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 
 describe("prints information for debugging AST --debug-print-ast", () => {
   runPrettier("cli/with-shebang", ["--debug-print-ast", "--parser", "babel"], {
diff --git a/tests/integration/__tests__/debug-print-comments.js b/tests/integration/__tests__/debug-print-comments.js
index 5b10539f3..2b1f1f99f 100644
--- a/tests/integration/__tests__/debug-print-comments.js
+++ b/tests/integration/__tests__/debug-print-comments.js
@@ -1,6 +1,6 @@
 "use strict";
 
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 
 describe("prints information for debugging comment attachment with --debug-print-comments", () => {
   runPrettier(
diff --git a/tests/integration/__tests__/debug-print-doc.js b/tests/integration/__tests__/debug-print-doc.js
index b165b6c93..4954bb448 100644
--- a/tests/integration/__tests__/debug-print-doc.js
+++ b/tests/integration/__tests__/debug-print-doc.js
@@ -1,6 +1,6 @@
 "use strict";
 
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 
 describe("prints doc with --debug-print-doc", () => {
   runPrettier("cli/with-shebang", ["--debug-print-doc", "--parser", "babel"], {
diff --git a/tests/integration/__tests__/early-exit.js b/tests/integration/__tests__/early-exit.js
index 85277ba5a..8cf36ed21 100644
--- a/tests/integration/__tests__/early-exit.js
+++ b/tests/integration/__tests__/early-exit.js
@@ -1,7 +1,7 @@
 "use strict";
 
 const prettier = require("prettier-local");
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 const { isProduction } = require("../env.js");
 
 describe("show version with --version", () => {
diff --git a/tests/integration/__tests__/error-on-unmatched-pattern.js b/tests/integration/__tests__/error-on-unmatched-pattern.js
index 0cea212d3..36bf16aed 100644
--- a/tests/integration/__tests__/error-on-unmatched-pattern.js
+++ b/tests/integration/__tests__/error-on-unmatched-pattern.js
@@ -1,6 +1,6 @@
 "use strict";
 
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 
 describe("no error on unmatched pattern", () => {
   runPrettier("cli/error-on-unmatched-pattern", [
diff --git a/tests/integration/__tests__/file-info.js b/tests/integration/__tests__/file-info.js
index 009b36820..e121e505e 100644
--- a/tests/integration/__tests__/file-info.js
+++ b/tests/integration/__tests__/file-info.js
@@ -6,7 +6,7 @@ const tempy = require("tempy");
 const fromPairs = require("lodash/fromPairs");
 
 const prettier = require("prettier-local");
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 
 expect.addSnapshotSerializer(require("../path-serializer.js"));
 
diff --git a/tests/integration/__tests__/help-options.js b/tests/integration/__tests__/help-options.js
index f87acfa2f..fb03f529e 100644
--- a/tests/integration/__tests__/help-options.js
+++ b/tests/integration/__tests__/help-options.js
@@ -1,7 +1,7 @@
 "use strict";
 
 const prettier = require("prettier-local");
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 const constant = require("../../../src/cli/constant.js");
 const {
   createDetailedOptionMap,
diff --git a/tests/integration/__tests__/ignore-absolute-path.js b/tests/integration/__tests__/ignore-absolute-path.js
index 79fde347f..23749ded2 100644
--- a/tests/integration/__tests__/ignore-absolute-path.js
+++ b/tests/integration/__tests__/ignore-absolute-path.js
@@ -1,7 +1,7 @@
 "use strict";
 
 const path = require("path");
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 
 describe("support absolute filename", () => {
   runPrettier("cli/ignore-absolute-path", [
diff --git a/tests/integration/__tests__/ignore-emoji.js b/tests/integration/__tests__/ignore-emoji.js
index a18ff4e90..41939a4cf 100644
--- a/tests/integration/__tests__/ignore-emoji.js
+++ b/tests/integration/__tests__/ignore-emoji.js
@@ -1,6 +1,6 @@
 "use strict";
 
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 
 expect.addSnapshotSerializer(require("../path-serializer.js"));
 
diff --git a/tests/integration/__tests__/ignore-in-subdirectories.js b/tests/integration/__tests__/ignore-in-subdirectories.js
index b30d361fe..e99e1015e 100644
--- a/tests/integration/__tests__/ignore-in-subdirectories.js
+++ b/tests/integration/__tests__/ignore-in-subdirectories.js
@@ -1,6 +1,6 @@
 "use strict";
 
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 
 expect.addSnapshotSerializer(require("../path-serializer.js"));
 
diff --git a/tests/integration/__tests__/ignore-path.js b/tests/integration/__tests__/ignore-path.js
index b7877a1bd..63dd2451f 100644
--- a/tests/integration/__tests__/ignore-path.js
+++ b/tests/integration/__tests__/ignore-path.js
@@ -2,7 +2,7 @@
 
 const fs = require("fs");
 const path = require("path");
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 
 fs.writeFileSync(
   // This file is in `.gitignore`, just copy from `regular-module.js`
diff --git a/tests/integration/__tests__/ignore-relative-path.js b/tests/integration/__tests__/ignore-relative-path.js
index 85a0939cd..8bb7525a5 100644
--- a/tests/integration/__tests__/ignore-relative-path.js
+++ b/tests/integration/__tests__/ignore-relative-path.js
@@ -1,6 +1,6 @@
 "use strict";
 
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 
 expect.addSnapshotSerializer(require("../path-serializer.js"));
 
diff --git a/tests/integration/__tests__/ignore-unknown.js b/tests/integration/__tests__/ignore-unknown.js
index 13846a720..68967e173 100644
--- a/tests/integration/__tests__/ignore-unknown.js
+++ b/tests/integration/__tests__/ignore-unknown.js
@@ -1,6 +1,6 @@
 "use strict";
 
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 
 describe("ignore-unknown dir", () => {
   runPrettier("cli/ignore-unknown", [
diff --git a/tests/integration/__tests__/ignore-vcs-files.js b/tests/integration/__tests__/ignore-vcs-files.js
index 058bd15f6..a6416647b 100644
--- a/tests/integration/__tests__/ignore-vcs-files.js
+++ b/tests/integration/__tests__/ignore-vcs-files.js
@@ -1,6 +1,6 @@
 "use strict";
 
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 
 expect.addSnapshotSerializer(require("../path-serializer.js"));
 
diff --git a/tests/integration/__tests__/infer-parser.js b/tests/integration/__tests__/infer-parser.js
index bd98fa819..029a5abf6 100644
--- a/tests/integration/__tests__/infer-parser.js
+++ b/tests/integration/__tests__/infer-parser.js
@@ -1,7 +1,7 @@
 "use strict";
 
 const prettier = require("prettier-local");
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 
 describe("stdin no path and no parser", () => {
   describe("logs error and exits with 2", () => {
diff --git a/tests/integration/__tests__/invalid-ignore.js b/tests/integration/__tests__/invalid-ignore.js
index 55ed1cc7a..6902461bd 100644
--- a/tests/integration/__tests__/invalid-ignore.js
+++ b/tests/integration/__tests__/invalid-ignore.js
@@ -2,7 +2,7 @@
 
 const path = require("path");
 const prettier = require("prettier-local");
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 
 expect.addSnapshotSerializer(require("../path-serializer.js"));
 
diff --git a/tests/integration/__tests__/line-suffix-boundary.js b/tests/integration/__tests__/line-suffix-boundary.js
index 8e1cd7a03..e74dc58b6 100644
--- a/tests/integration/__tests__/line-suffix-boundary.js
+++ b/tests/integration/__tests__/line-suffix-boundary.js
@@ -6,7 +6,7 @@ const prettier = require("prettier-local");
 const { group, indent, line, lineSuffix, lineSuffixBoundary, softline } =
   prettier.doc.builders;
 
-const printDoc = require("../printDoc.js");
+const printDoc = require("../print-doc.js");
 
 describe("lineSuffixBoundary", () => {
   test("should be correctly treated as a potential line break in `fits`", () => {
diff --git a/tests/integration/__tests__/list-different.js b/tests/integration/__tests__/list-different.js
index 2de416d56..4eada3755 100644
--- a/tests/integration/__tests__/list-different.js
+++ b/tests/integration/__tests__/list-different.js
@@ -1,6 +1,6 @@
 "use strict";
 
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 
 describe("checks stdin with --list-different", () => {
   runPrettier("cli/with-shebang", ["--list-different", "--parser", "babel"], {
diff --git a/tests/integration/__tests__/loglevel.js b/tests/integration/__tests__/loglevel.js
index bb9bc3319..51d745e38 100644
--- a/tests/integration/__tests__/loglevel.js
+++ b/tests/integration/__tests__/loglevel.js
@@ -1,7 +1,7 @@
 "use strict";
 
 const stripAnsi = require("strip-ansi");
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 
 test("do not show logs with --loglevel silent", async () => {
   await runPrettierWithLogLevel("silent", null);
diff --git a/tests/integration/__tests__/parser-api.js b/tests/integration/__tests__/parser-api.js
index 8f88a67a5..b9e69de25 100644
--- a/tests/integration/__tests__/parser-api.js
+++ b/tests/integration/__tests__/parser-api.js
@@ -1,7 +1,7 @@
 "use strict";
 
 const prettier = require("prettier-local");
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 
 test("allows custom parser provided as object", () => {
   const output = prettier.format("1", {
diff --git a/tests/integration/__tests__/patterns-dirs.js b/tests/integration/__tests__/patterns-dirs.js
index 803b41377..3d8546bc5 100644
--- a/tests/integration/__tests__/patterns-dirs.js
+++ b/tests/integration/__tests__/patterns-dirs.js
@@ -2,7 +2,7 @@
 
 const path = require("path");
 const fs = require("fs");
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 const { projectRoot } = require("../env.js");
 
 expect.addSnapshotSerializer(require("../path-serializer.js"));
diff --git a/tests/integration/__tests__/patterns-glob.js b/tests/integration/__tests__/patterns-glob.js
index 4bb648939..e69acf18f 100644
--- a/tests/integration/__tests__/patterns-glob.js
+++ b/tests/integration/__tests__/patterns-glob.js
@@ -1,6 +1,6 @@
 "use strict";
 
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 
 expect.addSnapshotSerializer(require("../path-serializer.js"));
 
diff --git a/tests/integration/__tests__/patterns.js b/tests/integration/__tests__/patterns.js
index 455829833..ccf494aaf 100644
--- a/tests/integration/__tests__/patterns.js
+++ b/tests/integration/__tests__/patterns.js
@@ -1,6 +1,6 @@
 "use strict";
 
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 
 expect.addSnapshotSerializer(require("../path-serializer.js"));
 
diff --git a/tests/integration/__tests__/piped-output.js b/tests/integration/__tests__/piped-output.js
index 004c5eb89..fdadb0dbb 100644
--- a/tests/integration/__tests__/piped-output.js
+++ b/tests/integration/__tests__/piped-output.js
@@ -1,6 +1,6 @@
 "use strict";
 
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 
 describe("output with --check + unformatted differs when piped", () => {
   const cli0 = runPrettier(
diff --git a/tests/integration/__tests__/plugin-default-options.js b/tests/integration/__tests__/plugin-default-options.js
index 76c9f4002..31e28e85e 100644
--- a/tests/integration/__tests__/plugin-default-options.js
+++ b/tests/integration/__tests__/plugin-default-options.js
@@ -1,6 +1,6 @@
 "use strict";
 
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 
 describe("plugin default options should work", () => {
   runPrettier(
diff --git a/tests/integration/__tests__/plugin-extensions.js b/tests/integration/__tests__/plugin-extensions.js
index 2bba45602..d9ab5a6f1 100644
--- a/tests/integration/__tests__/plugin-extensions.js
+++ b/tests/integration/__tests__/plugin-extensions.js
@@ -1,6 +1,6 @@
 "use strict";
 
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 const EOL = "\n";
 
 describe("uses 'extensions' from languages to determine parser", () => {
diff --git a/tests/integration/__tests__/plugin-flush-line-suffix.js b/tests/integration/__tests__/plugin-flush-line-suffix.js
index 0ed261439..7487783fd 100644
--- a/tests/integration/__tests__/plugin-flush-line-suffix.js
+++ b/tests/integration/__tests__/plugin-flush-line-suffix.js
@@ -1,6 +1,6 @@
 "use strict";
 
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 
 describe("flush all line-suffix content", () => {
   runPrettier("plugins/flushLineSuffix", ["*.foo", "--plugin=./plugin"], {
diff --git a/tests/integration/__tests__/plugin-options-string.js b/tests/integration/__tests__/plugin-options-string.js
index 1dd3a4d88..dea3b778a 100644
--- a/tests/integration/__tests__/plugin-options-string.js
+++ b/tests/integration/__tests__/plugin-options-string.js
@@ -1,7 +1,7 @@
 "use strict";
 
 const snapshotDiff = require("snapshot-diff");
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 
 test("show external options with `--help`", async () => {
   const originalStdout = await runPrettier("plugins/options-string", ["--help"])
diff --git a/tests/integration/__tests__/plugin-options.js b/tests/integration/__tests__/plugin-options.js
index 22cafb738..4e9f69998 100644
--- a/tests/integration/__tests__/plugin-options.js
+++ b/tests/integration/__tests__/plugin-options.js
@@ -1,7 +1,7 @@
 "use strict";
 
 const snapshotDiff = require("snapshot-diff");
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 
 test("show external options with `--help`", async () => {
   const originalStdout = await runPrettier("plugins/options", ["--help"])
diff --git a/tests/integration/__tests__/plugin-precedence.js b/tests/integration/__tests__/plugin-precedence.js
index 0770ab4b5..e22985324 100644
--- a/tests/integration/__tests__/plugin-precedence.js
+++ b/tests/integration/__tests__/plugin-precedence.js
@@ -1,6 +1,6 @@
 "use strict";
 
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 
 describe("json-stringify takes precedence over json for package.json", () => {
   runPrettier("plugins", ["--stdin-filepath=package.json"], {
diff --git a/tests/integration/__tests__/plugin-preprocess.js b/tests/integration/__tests__/plugin-preprocess.js
index 0c0452e42..2d0457b19 100644
--- a/tests/integration/__tests__/plugin-preprocess.js
+++ b/tests/integration/__tests__/plugin-preprocess.js
@@ -1,6 +1,6 @@
 "use strict";
 
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 const EOL = "\n";
 
 describe("parser preprocess function is used to reshape input text", () => {
diff --git a/tests/integration/__tests__/plugin-resolution.js b/tests/integration/__tests__/plugin-resolution.js
index 8b51b7866..55118184b 100644
--- a/tests/integration/__tests__/plugin-resolution.js
+++ b/tests/integration/__tests__/plugin-resolution.js
@@ -1,6 +1,6 @@
 "use strict";
 
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 const EOL = "\n";
 
 describe("automatically loads 'prettier-plugin-*'", () => {
diff --git a/tests/integration/__tests__/plugin-virtual-directory.js b/tests/integration/__tests__/plugin-virtual-directory.js
index 44c95f6c4..280562d4b 100644
--- a/tests/integration/__tests__/plugin-virtual-directory.js
+++ b/tests/integration/__tests__/plugin-virtual-directory.js
@@ -1,6 +1,6 @@
 "use strict";
 
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 
 describe("plugin search should not crash when prettier isn't inside a directory", () => {
   runPrettier(
diff --git a/tests/integration/__tests__/skip-folders.js b/tests/integration/__tests__/skip-folders.js
index dd1ea822b..fda9a2efb 100644
--- a/tests/integration/__tests__/skip-folders.js
+++ b/tests/integration/__tests__/skip-folders.js
@@ -1,6 +1,6 @@
 "use strict";
 
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 
 expect.addSnapshotSerializer(require("../path-serializer.js"));
 
diff --git a/tests/integration/__tests__/stdin-filepath.js b/tests/integration/__tests__/stdin-filepath.js
index 53f53b8e1..5be8c05d5 100644
--- a/tests/integration/__tests__/stdin-filepath.js
+++ b/tests/integration/__tests__/stdin-filepath.js
@@ -1,7 +1,7 @@
 "use strict";
 
 const { isCI } = require("ci-info");
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 
 describe("format correctly if stdin content compatible with stdin-filepath", () => {
   runPrettier(
diff --git a/tests/integration/__tests__/support-info.js b/tests/integration/__tests__/support-info.js
index 57cd9d7df..017d6af5d 100644
--- a/tests/integration/__tests__/support-info.js
+++ b/tests/integration/__tests__/support-info.js
@@ -1,7 +1,7 @@
 "use strict";
 
 const prettier = require("prettier-local");
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 
 test("API getSupportInfo()", () => {
   expect(getCoreInfo()).toMatchSnapshot();
diff --git a/tests/integration/__tests__/syntax-error.js b/tests/integration/__tests__/syntax-error.js
index e33c23e5b..a4d043068 100644
--- a/tests/integration/__tests__/syntax-error.js
+++ b/tests/integration/__tests__/syntax-error.js
@@ -1,6 +1,6 @@
 "use strict";
 
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 
 describe("exits with non-zero code when input has a syntax error", () => {
   runPrettier("cli/with-shebang", ["--parser", "babel"], {
diff --git a/tests/integration/__tests__/with-config-precedence.js b/tests/integration/__tests__/with-config-precedence.js
index 39944e10f..ff1d0592b 100644
--- a/tests/integration/__tests__/with-config-precedence.js
+++ b/tests/integration/__tests__/with-config-precedence.js
@@ -1,6 +1,6 @@
 "use strict";
 
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 
 describe("CLI overrides take precedence without --config-precedence", () => {
   runPrettier("cli/config/", [
diff --git a/tests/integration/__tests__/with-node-modules.js b/tests/integration/__tests__/with-node-modules.js
index 689b9eafa..a9cb5ef56 100644
--- a/tests/integration/__tests__/with-node-modules.js
+++ b/tests/integration/__tests__/with-node-modules.js
@@ -1,6 +1,6 @@
 "use strict";
 
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 
 expect.addSnapshotSerializer(require("../path-serializer.js"));
 
diff --git a/tests/integration/__tests__/with-parser-inference.js b/tests/integration/__tests__/with-parser-inference.js
index caacb5d48..3dd4fc913 100644
--- a/tests/integration/__tests__/with-parser-inference.js
+++ b/tests/integration/__tests__/with-parser-inference.js
@@ -1,7 +1,7 @@
 "use strict";
 
 const prettier = require("prettier-local");
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 
 describe("infers postcss parser", () => {
   runPrettier("cli/with-parser-inference", ["--end-of-line", "lf", "*"]).test({
diff --git a/tests/integration/__tests__/with-shebang.js b/tests/integration/__tests__/with-shebang.js
index 7d9e7bae7..7b4fe264d 100644
--- a/tests/integration/__tests__/with-shebang.js
+++ b/tests/integration/__tests__/with-shebang.js
@@ -1,6 +1,6 @@
 "use strict";
 
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 
 describe("preserves shebang", () => {
   runPrettier("cli/with-shebang", ["--end-of-line", "lf", "issue1890.js"]).test(
diff --git a/tests/integration/__tests__/write.js b/tests/integration/__tests__/write.js
index a649af391..ae702be37 100644
--- a/tests/integration/__tests__/write.js
+++ b/tests/integration/__tests__/write.js
@@ -1,6 +1,6 @@
 "use strict";
 
-const runPrettier = require("../runPrettier.js");
+const runPrettier = require("../run-prettier.js");
 
 describe("write file with --write + unformatted file", () => {
   runPrettier("cli/write", ["--write", "unformatted.js"]).test({
diff --git a/tests/integration/printDoc.js b/tests/integration/print-doc.js
similarity index 100%
rename from tests/integration/printDoc.js
rename to tests/integration/print-doc.js
diff --git a/tests/integration/runPrettier.js b/tests/integration/run-prettier.js
similarity index 100%
rename from tests/integration/runPrettier.js
rename to tests/integration/run-prettier.js