path: Remove dead code in favor of unit tests

Remove dead code paths that are created by assertions that will never
trigger. They may only trigger if either the `splitDeviceRe` or
`splitPathRe` regular expressions are modified. If at some point they
are modified, current unit tests will catch most of the resulting
errors and this commit adds extra tests to catch the remaining errors.

Author: nwoltman

lib/path.js

@@ -90,7 +90,7 @@ function win32SplitPath(filename) {
   // Separate device+slash from tail
   var result = splitDeviceRe.exec(filename),
       device = (result[1] || '') + (result[2] || ''),
-      tail = result[3] || '';
+      tail = result[3];
   // Split the tail into dir, basename and extension
   var result2 = splitTailRe.exec(tail),
       dir = result2[1],
@@ -392,13 +392,10 @@ win32.format = function(pathObject) {
 win32.parse = function(pathString) {
   if (!util.isString(pathString)) {
     throw new TypeError(
-        "Parameter 'pathString' must be a string, not " + typeof pathString
+      "Parameter 'pathString' must be a string, not " + typeof pathString
     );
   }
   var allParts = win32SplitPath(pathString);
-  if (!allParts || allParts.length !== 4) {
-    throw new TypeError("Invalid path '" + pathString + "'");
-  }
   return {
     root: allParts[0],
     dir: allParts[0] + allParts[1].slice(0, -1),
@@ -592,17 +589,10 @@ posix.format = function(pathObject) {
 posix.parse = function(pathString) {
   if (!util.isString(pathString)) {
     throw new TypeError(
-        "Parameter 'pathString' must be a string, not " + typeof pathString
+      "Parameter 'pathString' must be a string, not " + typeof pathString
     );
   }
   var allParts = posixSplitPath(pathString);
-  if (!allParts || allParts.length !== 4) {
-    throw new TypeError("Invalid path '" + pathString + "'");
-  }
-  allParts[1] = allParts[1] || '';
-  allParts[2] = allParts[2] || '';
-  allParts[3] = allParts[3] || '';
-
   return {
     root: allParts[0],
     dir: allParts[0] + allParts[1].slice(0, -1),

test/simple/test-path-parse-format.js

@@ -29,6 +29,7 @@ var winPaths = [
   '\\foo\\C:',
   'file',
   '.\\file',
+  '',
 
   // unc
   '\\\\server\\share\\file_path',
@@ -52,7 +53,8 @@ var unixPaths = [
   'file',
   '.\\file',
   './file',
-  'C:\\foo'
+  'C:\\foo',
+  ''
 ];
 
 var unixSpecialCaseFormatTests = [
@@ -67,7 +69,6 @@ var errors = [
   {method: 'parse', input: [true], message: /Parameter 'pathString' must be a string, not boolean/},
   {method: 'parse', input: [1], message: /Parameter 'pathString' must be a string, not number/},
   {method: 'parse', input: [], message: /Parameter 'pathString' must be a string, not undefined/},
-  // {method: 'parse', input: [''], message: /Invalid path/}, // omitted because it's hard to trigger!
   {method: 'format', input: [null], message: /Parameter 'pathObject' must be an object, not/},
   {method: 'format', input: [''], message: /Parameter 'pathObject' must be an object, not string/},
   {method: 'format', input: [true], message: /Parameter 'pathObject' must be an object, not boolean/},
@@ -101,8 +102,13 @@ function checkErrors(path) {
 }
 
 function checkParseFormat(path, paths) {
-  paths.forEach(function(element, index, array) {
+  paths.forEach(function(element) {
     var output = path.parse(element);
+    assert.strictEqual(typeof output.root, 'string');
+    assert.strictEqual(typeof output.dir, 'string');
+    assert.strictEqual(typeof output.base, 'string');
+    assert.strictEqual(typeof output.ext, 'string');
+    assert.strictEqual(typeof output.name, 'string');
     assert.strictEqual(path.format(output), element);
     assert.strictEqual(output.dir, output.dir ? path.dirname(element) : '');
     assert.strictEqual(output.base, path.basename(element));