December fixes (scottrogowski#35)

* improve dependency robustness. Fix Python import bug. Small text improvements

* include acorn dependency

* add acorn package

* add python test for relative paths

* fix eof newlines

Co-authored-by: Scott <scott@Scotts-MacBook-Pro.local>

Author: scottrogowski

README.md

@@ -31,6 +31,12 @@ pip3 install code2flow
 
 If you don't have it already, you will also need to install graphviz. Installation instructions can be found [here](https://graphviz.org/download/).
 
+Additionally, depending on the language you want to parse, you may need to install additional dependencies:
+- Javascript: [Acorn](https://www.npmjs.com/package/acorn)
+- Ruby: [Parser](https://github.com/whitequark/parser)
+- PHP: [PHP-Parser](https://github.com/nikic/PHP-Parser)
+- Python: No extra dependencies needed
+
 Usage
 -----
 
@@ -142,6 +148,15 @@ Unrelated projects
 The name, "code2flow", has been used for several unrelated projects. Specifically, the domain, code2flow.com, has no association with this project. I've never heard anything from them and it doesn't appear like they use anything from here.
 
 
+Unit tests
+------------------
+
+Test coverage is 100%. To run:
+
+    pip install -r requirements_dev.txt
+    make test
+
+
 Feedback / Contact
 -----------------------------
 

code2flow/engine.py

@@ -197,7 +197,7 @@ def make_file_group(tree, filename, extension):
     token = os.path.split(filename)[-1].rsplit('.' + extension, 1)[0]
     line_number = 0
     display_name = 'File'
-    import_tokens = []
+    import_tokens = language.file_import_tokens(filename)
 
     file_group = Group(token, group_type, display_name, import_tokens,
                        line_number, parent=None)

code2flow/javascript.py

@@ -234,8 +234,13 @@ def get_acorn_version():
     Get the version of installed acorn
     :rtype: str
     """
-    outp = subprocess.check_output(['node', '-p', 'require(\'acorn/package.json\').version'])
-    return outp.decode().strip()
+    proc = subprocess.Popen(['node', '-p', 'require(\'acorn/package.json\').version'],
+                            stdout=subprocess.PIPE, stderr=subprocess.PIPE,
+                            cwd=os.path.dirname(os.path.realpath(__file__)))
+    assert proc.wait() == 0, "Acorn is required to parse javascript files. " \
+                             "It was found on the path but could not be imported " \
+                             "in node.\n" + proc.stderr.read().decode()
+    return proc.stdout.read().decode().strip()
 
 
 class Javascript(BaseLanguage):
@@ -398,3 +403,13 @@ def make_class_group(tree, parent):
                 class_group.add_node(new_node)
 
         return class_group
+
+    @staticmethod
+    def file_import_tokens(filename):
+        """
+        Returns the token(s) we would use if importing this file from another.
+
+        :param filename str:
+        :rtype: list[str]
+        """
+        return []