Try using node+rapydscript on appveyor as well

.appveyor.yml

@@ -5,6 +5,15 @@ clone_depth: 5
 
 cache:
     - .build-cache
+    - node_modules -> .appveyor.yml
+
+install:
+    - ps: Install-Product node 7
+    - node --version
+    - npm --version
+    - appveyor-retry npm install --no-optional rapydscript-ng regenerator uglify-js
+    - set PATH=node_modules\.bin;%PATH%
+    - rapydscript --version
 
 environment:
     SW: C:\sw

setup/win-ci.py

@@ -184,7 +184,7 @@ def sw():
 
 def sanitize_path():
     needed_paths = []
-    executables = 'git.exe curl.exe'.split()
+    executables = 'git.exe curl.exe rapydscript.cmd node.exe'.split()
     for p in os.environ['PATH'].split(os.pathsep):
         for x in tuple(executables):
             if os.path.exists(os.path.join(p, x)):
@@ -195,6 +195,7 @@ def sanitize_path():
         sw
     ).split() + needed_paths
     os.environ[b'PATH'] = os.pathsep.join(paths).encode('ascii')
+    print('PATH:', os.environ[b'PATH'])
 
 
 def vcenv():

src/calibre/utils/filenames.py

@@ -93,13 +93,13 @@ def shorten_components_to(length, components, more_to_take=0, last_has_extension
 def find_executable_in_path(name, path=None):
     if path is None:
         path = os.environ.get('PATH', '')
-    if iswindows and not name.endswith('.exe'):
-        name += '.exe'
+    exts = '.exe .cmd .bat'.split() if iswindows and not name.endswith('.exe') else ('',)
     path = path.split(os.pathsep)
     for x in path:
-        q = os.path.abspath(os.path.join(x, name))
-        if os.access(q, os.X_OK):
-            return q
+        for ext in exts:
+            q = os.path.abspath(os.path.join(x, name)) + ext
+            if os.access(q, os.X_OK):
+                return q
 
 
 def is_case_sensitive(path):