diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 913b1bf371..1cd9a78e57 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -326,17 +326,12 @@ jobs:
         run: ./scripts/prebuilt.js
 
       - name: Run tests
-        if: runner.os != 'Windows'
         run: node scripts/test.js -all
 
       - name: Run gentype tests
         if: runner.os != 'Windows'
         run: make -C tests/gentype_tests/typescript-react-example clean test
 
-      - name: Run tests (Windows)
-        if: runner.os == 'Windows'
-        run: node scripts/test.js -mocha -theme -format
-
       - name: Build playground compiler
         if: matrix.build_playground
         run: |
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 80ba6dbb4f..b144bb80c8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -46,6 +46,7 @@
 - Remove uncurried flag from bsb. https://github.com/rescript-lang/rescript-compiler/pull/7049
 - Build runtime/stdlib files with rescript/bsb instead of ninja.js. https://github.com/rescript-lang/rescript-compiler/pull/7063
 - Build tests with bsb and move them out of jscomp. https://github.com/rescript-lang/rescript-compiler/pull/7068
+- Run `build_tests` on Windows. https://github.com/rescript-lang/rescript-compiler/pull/7065
 
 # 12.0.0-alpha.3
 
diff --git a/scripts/test.js b/scripts/test.js
index c6c45ef840..ebba6688c9 100644
--- a/scripts/test.js
+++ b/scripts/test.js
@@ -2,7 +2,7 @@
 const cp = require("child_process");
 const path = require("path");
 const fs = require("fs");
-var { rescript_exe } = require("#cli/bin_path");
+const { rescript_exe } = require("#cli/bin_path");
 
 const duneBinDir = require("./dune").duneBinDir;
 
@@ -50,9 +50,13 @@ async function runTests() {
   }
 
   if (ounitTest) {
-    cp.execSync(path.join(duneBinDir, "ounit_tests"), {
-      stdio: [0, 1, 2],
-    });
+    if (process.platform === "win32") {
+      console.log("Skipping OUnit tests on Windows");
+    } else {
+      cp.execSync(path.join(duneBinDir, "ounit_tests"), {
+        stdio: [0, 1, 2],
+      });
+    }
   }
 
   if (mochaTest) {
diff --git a/tests/build_tests/case/input.js b/tests/build_tests/case/input.js
index 8e5cced399..b3cbcc4d85 100644
--- a/tests/build_tests/case/input.js
+++ b/tests/build_tests/case/input.js
@@ -1,14 +1,18 @@
 var p = require("child_process");
 var assert = require("assert");
 var { rescript_exe } = require("#cli/bin_path");
+var { normalizeNewlines } = require("../utils.js");
+
 var o = p.spawnSync(rescript_exe, { encoding: "utf8", cwd: __dirname });
 
 if (
   ![
     `Error: Invalid bsconfig.json implementation and interface have different path names or different cases src/demo vs src/Demo\n`,
-    // On linux files are parsed in different order
+    // Windows: path separator
+    `Error: Invalid bsconfig.json implementation and interface have different path names or different cases src\\demo vs src\\Demo\n`,
+    // Linux: files are parsed in different order
     `Error: Invalid bsconfig.json implementation and interface have different path names or different cases src/Demo vs src/demo\n`,
-  ].includes(o.stderr)
+  ].includes(normalizeNewlines(o.stderr))
 ) {
   assert.fail(o.stderr);
 }
diff --git a/tests/build_tests/case2/input.js b/tests/build_tests/case2/input.js
index a4a3245189..421017507e 100644
--- a/tests/build_tests/case2/input.js
+++ b/tests/build_tests/case2/input.js
@@ -1,14 +1,18 @@
 var p = require("child_process");
 var assert = require("assert");
 var { rescript_exe } = require("#cli/bin_path");
+var { normalizeNewlines } = require("../utils.js");
+
 var o = p.spawnSync(rescript_exe, { encoding: "utf8", cwd: __dirname });
 
 if (
   ![
     `Error: Invalid bsconfig.json implementation and interface have different path names or different cases src/X vs src/x\n`,
-    // On linux files are parsed in different order
+    // Windows: path separator
+    `Error: Invalid bsconfig.json implementation and interface have different path names or different cases src\\X vs src\\x\n`,
+    // Linux: files are parsed in different order
     `Error: Invalid bsconfig.json implementation and interface have different path names or different cases src/x vs src/X\n`,
-  ].includes(o.stderr)
+  ].includes(normalizeNewlines(o.stderr))
 ) {
   assert.fail(o.stderr);
 }
diff --git a/tests/build_tests/cli_compile_status/input.js b/tests/build_tests/cli_compile_status/input.js
index 90f72542c3..48365fc321 100755
--- a/tests/build_tests/cli_compile_status/input.js
+++ b/tests/build_tests/cli_compile_status/input.js
@@ -1,27 +1,31 @@
 // @ts-check
 
 const assert = require("assert");
+const path = require("path");
 const child_process = require("child_process");
+const { normalizeNewlines } = require("../utils.js");
+
+const rescriptPath = path.join(__dirname, "..", "..", "..", "rescript")
 
 // Shows compile time for `rescript build` command
-let out = child_process.spawnSync(`../../../rescript`, ["build"], {
+let out = child_process.spawnSync("node", [rescriptPath, "build"], {
   encoding: "utf8",
   cwd: __dirname,
 });
 assert.match(
-  out.stdout,
+  normalizeNewlines(out.stdout),
   new RegExp(`>>>> Start compiling
 Dependency Finished
 >>>> Finish compiling \\d+ mseconds`),
 );
 
 // Shows compile time for `rescript` command
-out = child_process.spawnSync(`../../../rescript`, {
+out = child_process.spawnSync("node", [rescriptPath], {
   encoding: "utf8",
   cwd: __dirname,
 });
 assert.match(
-  out.stdout,
+  normalizeNewlines(out.stdout),
   new RegExp(`>>>> Start compiling
 Dependency Finished
 >>>> Finish compiling \\d+ mseconds`),
@@ -31,13 +35,10 @@ Dependency Finished
 // Because we can't be sure that -verbose is a valid argument
 // And bsb won't fail with a usage message.
 // It works this way not only for -verbose, but any other arg, including -h/--help/-help
-out = child_process.spawnSync(`../../../rescript`, ["build", "-verbose"], {
+out = child_process.spawnSync("node", [rescriptPath, "build", "-verbose"], {
   encoding: "utf8",
   cwd: __dirname,
 });
-assert.match(
-  out.stdout,
-  new RegExp(
-    `Package stack: test  \nDependency Finished\nninja.exe -C lib/bs \n`,
-  ),
-);
+
+assert.match(normalizeNewlines(out.stdout), /Package stack: test  \nDependency Finished\n/);
+assert.match(normalizeNewlines(out.stdout), /ninja.exe"? -C lib[\\/]bs ?\n/);
diff --git a/tests/build_tests/cli_help/input.js b/tests/build_tests/cli_help/input.js
index 8fe5b9b9b4..7817c56450 100755
--- a/tests/build_tests/cli_help/input.js
+++ b/tests/build_tests/cli_help/input.js
@@ -1,7 +1,10 @@
 // @ts-check
 
 const assert = require("assert");
-const { exec } = require("../utils.js");
+const path = require("path");
+const { exec, normalizeNewlines } = require("../utils.js");
+
+const rescriptPath = path.join(__dirname, "..", "..", "..", "rescript")
 
 const cliHelp =
   "Usage: rescript <options> <subcommand>\n" +
@@ -61,184 +64,88 @@ const dumpHelp =
   "Usage: rescript dump <options> [target]\n" +
   "`rescript dump` dumps the information for the target\n";
 
+/**
+ * @param {string[]} params
+ * @param {{ stdout: string; stderr: string; status: number; }} expected
+ */
+async function runTest(params, expected) {
+  const out = await exec("node", [rescriptPath, ...params], {
+    cwd: __dirname,
+  });
+
+  assert.equal(normalizeNewlines(out.stdout), expected.stdout);
+  assert.equal(normalizeNewlines(out.stderr), expected.stderr);
+  assert.equal(out.status, expected.status);
+}
+  
 async function test() {
-  {
     // Shows build help with --help arg
-    const out = await exec(`../../../rescript`, ["build", "--help"], {
-      cwd: __dirname,
-    });
-    assert.equal(out.stdout, buildHelp);
-    assert.equal(out.stderr, "");
-    assert.equal(out.status, 0);
-  }
-
-  {
-    const out = await exec(`../../../rescript`, ["build", "-w", "--help"], {
-      cwd: __dirname,
-    });
-    assert.equal(out.stdout, buildHelp);
-    assert.equal(out.stderr, "");
-    assert.equal(out.status, 0);
-  }
-
-  {
-    const out = await exec(`../../../rescript`, ["-w", "--help"], {
-      cwd: __dirname,
-    });
-    assert.equal(out.stdout, cliHelp);
-    assert.equal(out.stderr, "");
-    assert.equal(out.status, 0);
-  }
-
-  {
-    // Shows cli help with --help arg even if there are invalid arguments after it
-    const out = await exec(`../../../rescript`, ["--help", "-w"], {
-      cwd: __dirname,
-    });
-    assert.equal(out.stdout, cliHelp);
-    assert.equal(out.stderr, "");
-    assert.equal(out.status, 0);
-  }
-
-  {
-    // Shows build help with -h arg
-    const out = await exec(`../../../rescript`, ["build", "-h"], {
-      cwd: __dirname,
-    });
-    assert.equal(out.stdout, buildHelp);
-    assert.equal(out.stderr, "");
-    assert.equal(out.status, 0);
-  }
-
-  {
-    // Exits with build help with unknown arg
-    const out = await exec(`../../../rescript`, ["build", "-foo"], {
-      cwd: __dirname,
-    });
-    assert.equal(out.stdout, "");
-    assert.equal(out.stderr, 'Error: Unknown option "-foo".\n' + buildHelp);
-    assert.equal(out.status, 2);
-  }
-
-  {
-    // Shows cli help with --help arg
-    const out = await exec(`../../../rescript`, ["--help"], {
-      cwd: __dirname,
-    });
-    assert.equal(out.stdout, cliHelp);
-    assert.equal(out.stderr, "");
-    assert.equal(out.status, 0);
-  }
-
-  {
-    // Shows cli help with -h arg
-    const out = await exec(`../../../rescript`, ["-h"], {
-      cwd: __dirname,
-    });
-    assert.equal(out.stdout, cliHelp);
-    assert.equal(out.stderr, "");
-    assert.equal(out.status, 0);
-  }
-
-  {
-    // Shows cli help with -h arg
-    const out = await exec(`../../../rescript`, ["help"], {
-      cwd: __dirname,
-    });
-    assert.equal(out.stdout, cliHelp);
-    assert.equal(out.stderr, "");
-    assert.equal(out.status, 0);
-  }
-
-  {
-    // Exits with cli help with unknown command
-    const out = await exec(`../../../rescript`, ["built"], {
-      cwd: __dirname,
-    });
-    assert.equal(out.stdout, "");
-    assert.equal(out.stderr, `Error: Unknown command "built".\n` + cliHelp);
-    assert.equal(out.status, 2);
-  }
-
-  {
-    // Exits with build help with unknown args
-    const out = await exec(`../../../rescript`, ["-foo"], {
-      cwd: __dirname,
-    });
-    assert.equal(out.stdout, "");
-    assert.equal(out.stderr, 'Error: Unknown option "-foo".\n' + buildHelp);
-    assert.equal(out.status, 2);
-  }
-
-  {
-    // Shows clean help with --help arg
-    const out = await exec(`../../../rescript`, ["clean", "--help"], {
-      cwd: __dirname,
-    });
-    assert.equal(out.stdout, cleanHelp);
-    assert.equal(out.stderr, "");
-    assert.equal(out.status, 0);
-  }
-
-  {
-    // Shows clean help with -h arg
-    const out = await exec(`../../../rescript`, ["clean", "-h"], {
-      cwd: __dirname,
-    });
-    assert.equal(out.stdout, cleanHelp);
-    assert.equal(out.stderr, "");
-    assert.equal(out.status, 0);
-  }
-
-  {
-    // Exits with clean help with unknown arg
-    const out = await exec(`../../../rescript`, ["clean", "-foo"], {
-      cwd: __dirname,
-    });
-    assert.equal(out.stdout, "");
-    assert.equal(out.stderr, 'Error: Unknown option "-foo".\n' + cleanHelp);
-    assert.equal(out.status, 2);
-  }
-
-  {
-    // Shows format help with --help arg
-    const out = await exec(`../../../rescript`, ["format", "--help"], {
-      cwd: __dirname,
-    });
-    assert.equal(out.stdout, formatHelp);
-    assert.equal(out.stderr, "");
-    assert.equal(out.status, 0);
-  }
-
-  {
-    // Shows format help with -h arg
-    const out = await exec(`../../../rescript`, ["format", "-h"], {
-      cwd: __dirname,
-    });
-    assert.equal(out.stdout, formatHelp);
-    assert.equal(out.stderr, "");
-    assert.equal(out.status, 0);
-  }
-
-  {
-    // Shows dump help with --help arg
-    const out = await exec(`../../../rescript`, ["dump", "--help"], {
-      cwd: __dirname,
-    });
-    assert.equal(out.stdout, dumpHelp);
-    assert.equal(out.stderr, "");
-    assert.equal(out.status, 0);
-  }
-
-  {
-    // Shows dump help with -h arg
-    const out = await exec(`../../../rescript`, ["dump", "-h"], {
-      cwd: __dirname,
-    });
-    assert.equal(out.stdout, dumpHelp);
-    assert.equal(out.stderr, "");
-    assert.equal(out.status, 0);
-  }
+  await runTest(["build", "--help"], { stdout: buildHelp, stderr: "", status: 0 });
+
+  await runTest(["build", "-w", "--help"], { stdout: buildHelp, stderr: "", status: 0 });
+
+  await runTest(["-w", "--help"], { stdout: cliHelp, stderr: "", status: 0 });
+
+  // Shows cli help with --help arg even if there are invalid arguments after it
+  await runTest(["--help", "-w"], { stdout: cliHelp, stderr: "", status: 0 });
+
+  // Shows build help with -h arg
+  await runTest(["build", "-h"], { stdout: buildHelp, stderr: "", status: 0 });
+
+  // Exits with build help with unknown arg
+  await runTest(["build", "-foo"], {
+    stdout: "",
+    stderr: 'Error: Unknown option "-foo".\n' + buildHelp,
+    status: 2,
+  });
+
+  // Shows cli help with --help arg
+  await runTest(["--help"], { stdout: cliHelp, stderr: "", status: 0 });
+
+  // Shows cli help with -h arg
+  await runTest(["-h"], { stdout: cliHelp, stderr: "", status: 0 });
+
+  // Shows cli help with -h arg
+  await runTest(["help"], { stdout: cliHelp, stderr: "", status: 0 });
+
+  // Exits with cli help with unknown command
+  await runTest(["built"], {
+    stdout: "",
+    stderr: `Error: Unknown command "built".\n` + cliHelp,
+    status: 2,
+  });
+
+  // Exits with build help with unknown args
+  await runTest(["-foo"], {
+    stdout: "",
+    stderr: 'Error: Unknown option "-foo".\n' + buildHelp,
+    status: 2,
+  });
+
+  // Shows clean help with --help arg
+  await runTest(["clean", "--help"], { stdout: cleanHelp, stderr: "", status: 0 });
+
+  // Shows clean help with -h arg
+  await runTest(["clean", "-h"], { stdout: cleanHelp, stderr: "", status: 0 });
+
+  // Exits with clean help with unknown arg
+  await runTest(["clean", "-foo"], {
+    stdout: "",
+    stderr: 'Error: Unknown option "-foo".\n' + cleanHelp,
+    status: 2,
+  });
+
+  // Shows format help with --help arg
+  await runTest(["format", "--help"], { stdout: formatHelp, stderr: "", status: 0 });
+
+  // Shows format help with -h arg
+  await runTest(["format", "-h"], { stdout: formatHelp, stderr: "", status: 0 });
+
+  // Shows dump help with --help arg
+  await runTest(["dump", "--help"], { stdout: dumpHelp, stderr: "", status: 0 });
+
+  // Shows dump help with -h arg
+  await runTest(["dump", "-h"], { stdout: dumpHelp, stderr: "", status: 0 });
 }
 
 void test();
diff --git a/tests/build_tests/duplicated_symlinked_packages/input.js b/tests/build_tests/duplicated_symlinked_packages/input.js
index b4f70bfd6a..a80c90d0d5 100644
--- a/tests/build_tests/duplicated_symlinked_packages/input.js
+++ b/tests/build_tests/duplicated_symlinked_packages/input.js
@@ -12,7 +12,14 @@ function postProcessErrorOutput(output) {
   output = output.replace(new RegExp(__dirname, "gi"), ".");
   return output;
 }
+
+if (process.platform === "win32") {
+  console.log("Skipping test on Windows");
+  process.exit(0);
+}
+
 child_process.execSync(`${rescript_exe} clean`, { cwd: __dirname });
+
 child_process.exec(rescript_exe, { cwd: __dirname }, (err, stdout, stderr) => {
   const actualErrorOutput = postProcessErrorOutput(stderr.toString());
   if (updateTests) {
diff --git a/tests/build_tests/post-build/input.js b/tests/build_tests/post-build/input.js
index 9cb97455d0..8a9b223f42 100644
--- a/tests/build_tests/post-build/input.js
+++ b/tests/build_tests/post-build/input.js
@@ -2,6 +2,11 @@ var child_process = require("child_process");
 var assert = require("assert");
 var { rescript_exe } = require("#cli/bin_path");
 
+if (process.platform === "win32") {
+  console.log("Skipping test on Windows");
+  process.exit(0);
+}
+
 var out = child_process.spawnSync(rescript_exe, { encoding: "utf8" });
 
 if (out.status !== 0) {
diff --git a/tests/build_tests/rerror/input.js b/tests/build_tests/rerror/input.js
index 18276be1cc..6f452f1331 100644
--- a/tests/build_tests/rerror/input.js
+++ b/tests/build_tests/rerror/input.js
@@ -1,10 +1,14 @@
+// @ts-check
 var child_process = require("child_process");
 var assert = require("assert");
+var os = require("os");
 var { rescript_exe } = require("#cli/bin_path");
+
 child_process.spawnSync(`${rescript_exe} clean`, {
   cwd: __dirname,
   encoding: "utf8",
 });
+
 var o = child_process.spawnSync(rescript_exe, {
   cwd: __dirname,
   encoding: "utf8",
@@ -15,16 +19,15 @@ var o = child_process.spawnSync(rescript_exe, {
 var u = o.stdout.match(/=>/g);
 
 var lines = o.stdout
-  .split("\n")
+  .split(/\r?\n/)
   .map(x => x.trim())
   .filter(Boolean);
-// console.log(`lines: \n${lines}`)
-// console.log(lines[4])
+
 var test = false;
 for (var i = 0; i < lines.length; ++i) {
   if (lines[i] === "We've found a bug for you!") {
     console.log(`line ${i} found`);
-    assert.ok(/src\/demo.res:1:21-23/.test(lines[i + 1]));
+    assert.ok(/src[\\/]demo.res:1:21-23/.test(lines[i + 1]));
     test = true;
   }
 }
diff --git a/tests/build_tests/scoped_ppx/input.js b/tests/build_tests/scoped_ppx/input.js
index 57815a9ef1..9d75560d0d 100644
--- a/tests/build_tests/scoped_ppx/input.js
+++ b/tests/build_tests/scoped_ppx/input.js
@@ -1,12 +1,19 @@
 var cp = require("child_process");
 var assert = require("assert");
 var { rescript_exe } = require("#cli/bin_path");
+
+if (process.platform === "win32") {
+  console.log("Skipping test on Windows");
+  process.exit(0);
+}
+
 cp.execSync(rescript_exe, { cwd: __dirname, encoding: "utf8" });
 
 var output = cp.execSync(`${rescript_exe} build -- -t commands src/hello.ast`, {
   cwd: __dirname,
   encoding: "utf8",
 });
+
 assert(
   /-ppx '.*\/test\.js -hello' -ppx '.*\/test\.js -heyy' -ppx .*test\.js/.test(
     output,
diff --git a/tests/build_tests/super_errors/input.js b/tests/build_tests/super_errors/input.js
index 958a538c8c..f7375a9933 100644
--- a/tests/build_tests/super_errors/input.js
+++ b/tests/build_tests/super_errors/input.js
@@ -3,6 +3,7 @@ const path = require("path");
 const child_process = require("child_process");
 
 const { bsc_exe: bsc } = require("#cli/bin_path");
+const { normalizeNewlines } = require("../utils.js");
 
 const expectedDir = path.join(__dirname, "expected");
 
@@ -15,13 +16,14 @@ const prefix = `${bsc} -w +A -bs-jsx 4 -bs-jsx-mode automatic`;
 
 const updateTests = process.argv[2] === "update";
 
+
 function postProcessErrorOutput(output) {
   output = output.trimRight();
   output = output.replace(
-    /\/[^ ]+?tests\/build_tests\/super_errors\//g,
-    "/.../",
+    /(?:[A-Z]:)?[\\/][^ ]+?tests[\\/]build_tests[\\/]super_errors[\\/]([^:]+)/g,
+    (_match, path, _offset, _string) => "/.../" + path.replace("\\", "/"),
   );
-  return output;
+  return normalizeNewlines(output);
 }
 
 let doneTasksCount = 0;
@@ -30,7 +32,6 @@ let atLeastOneTaskFailed = false;
 fixtures.forEach(fileName => {
   const fullFilePath = path.join(__dirname, "fixtures", fileName);
   const command = `${prefix} -color always ${fullFilePath}`;
-  console.log(`running ${command}`);
   child_process.exec(command, (err, stdout, stderr) => {
     doneTasksCount++;
     // careful of:
diff --git a/tests/build_tests/unboxed_bool_with_const/input.js b/tests/build_tests/unboxed_bool_with_const/input.js
index 2f5c856668..59b01f8273 100644
--- a/tests/build_tests/unboxed_bool_with_const/input.js
+++ b/tests/build_tests/unboxed_bool_with_const/input.js
@@ -3,6 +3,7 @@
 var cp = require("child_process");
 var assert = require("assert");
 var { rescript_exe } = require("#cli/bin_path");
+var { normalizeNewlines } = require("../utils.js");
 
 var out = cp.spawnSync(rescript_exe, {
   cwd: __dirname,
@@ -10,7 +11,7 @@ var out = cp.spawnSync(rescript_exe, {
 });
 
 assert.equal(
-  out.stdout.slice(out.stdout.indexOf("Main.res:3:3-14")),
+  normalizeNewlines(out.stdout.slice(out.stdout.indexOf("Main.res:3:3-14"))),
   `Main.res:3:3-14
 
   1 │ @unboxed
diff --git a/tests/build_tests/unicode/input.js b/tests/build_tests/unicode/input.js
index 9208b96e34..2e7443629b 100644
--- a/tests/build_tests/unicode/input.js
+++ b/tests/build_tests/unicode/input.js
@@ -1,11 +1,17 @@
 //@ts-check
 var child_process = require("child_process");
+var fs = require("fs");
+var path = require("path");
+
 var { rescript_exe } = require("#cli/bin_path");
 
+if (process.platform === "win32") {
+  console.log("Skipping test on Windows");
+  process.exit(0);
+}
+
 console.log(child_process.execSync(rescript_exe, { encoding: "utf8" }));
 
-var fs = require("fs");
-var path = require("path");
 var content =
   "" + fs.readFileSync(path.join(__dirname, "lib", "bs", ".sourcedirs.json"));
 
diff --git a/tests/build_tests/utils.js b/tests/build_tests/utils.js
index ac97290156..d0715e907f 100644
--- a/tests/build_tests/utils.js
+++ b/tests/build_tests/utils.js
@@ -49,4 +49,12 @@ async function exec(command, args, options) {
   });
 }
 
+/**
+ * @param {string} s
+ */
+function normalizeNewlines(s) {
+  return s.replace(/\r\n/g, '\n');
+}
+
 exports.exec = exec;
+exports.normalizeNewlines = normalizeNewlines;
diff --git a/tests/build_tests/weird_deps/input.js b/tests/build_tests/weird_deps/input.js
index 30d0fdd927..9199a61968 100644
--- a/tests/build_tests/weird_deps/input.js
+++ b/tests/build_tests/weird_deps/input.js
@@ -3,6 +3,7 @@
 var cp = require("child_process");
 var assert = require("assert");
 var { rescript_exe } = require("#cli/bin_path");
+var { normalizeNewlines } = require("../utils.js");
 
 var out = cp.spawnSync(rescript_exe, {
   cwd: __dirname,
@@ -13,7 +14,7 @@ if (out.stdout !== "") {
   assert.fail(out.stdout);
 } else {
   assert.equal(
-    out.stderr,
+    normalizeNewlines(out.stderr),
     [
       'File "bsconfig.json", line 1',
       "Error: package weird not found or built ",
diff --git a/tests/build_tests/weird_devdeps/input.js b/tests/build_tests/weird_devdeps/input.js
index 892b4bdf37..8bc6743ce5 100644
--- a/tests/build_tests/weird_devdeps/input.js
+++ b/tests/build_tests/weird_devdeps/input.js
@@ -2,6 +2,7 @@
 
 var cp = require("child_process");
 var assert = require("assert");
+var os = require("os");
 var rescript_exe = require("#cli/bin_path").rescript_exe;
 
 var out = cp.spawnSync(rescript_exe, {
@@ -19,6 +20,6 @@ if (out.stdout !== "") {
       "Error: package weird not found or built ",
       "- Did you install it?",
       "",
-    ].join("\n"),
+    ].join(os.EOL),
   );
 }