Update node_modules_path to resolve symlinks to real paths

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ### Fixes
 
+* `[jest-resolve]` Update node module resolution algorithm to follow physical paths ([#5085](https://github.com/facebook/jest/pull/5085))
 * `[jest-worker]` Remove `debug` and `inspect` flags from the arguments sent to
   the child ([#5068](https://github.com/facebook/jest/pull/5068))
 * `[jest-config]` Use all `--testPathPattern` and `<regexForTestFiles>` args in

packages/jest-resolve/src/node_modules_paths.js

@@ -11,6 +11,7 @@
 
 import type {Path} from 'types/Config';
 import path from 'path';
+import * as fs from 'fs';
 
 type NodeModulesPathsOptions = {|
   moduleDirectory?: Array<string>,
@@ -37,11 +38,16 @@ export default function nodeModulesPaths(
     prefix = '\\\\';
   }
 
-  const paths = [basedirAbs];
-  let parsed = path.parse(basedirAbs);
+  // we need to work with physical paths (i.e. follow symlinks to their
+  // true location), which is what the node resolution algorithm does
+  const physicalBasedir: string = fs.realpathSync(basedirAbs);
+
+  const paths = [physicalBasedir];
+  let parsed = path.parse(physicalBasedir);
   while (parsed.dir !== paths[paths.length - 1]) {
-    paths.push(parsed.dir);
-    parsed = path.parse(parsed.dir);
+    const realParsedDir: string = fs.realpathSync(parsed.dir);
+    paths.push(realParsedDir);
+    parsed = path.parse(realParsedDir);
   }
 
   const dirs = paths.reduce((dirs, aPath) => {