oetest.py: Add json file support to specify packages needed in runtime tests

This adds the functionality to use a json file to
specify the packages needed for a particular test.

The content of the json file is a dictionary with
dictionaries inside, using the test name as the hash.

The json file must have the same name as the class
module name and must be in the same path.

[YOCTO #7850]

(From OE-Core rev: 1f24ef9a339a2ad34e010f39aa93abdc8d085c85)

Signed-off-by: Mariano Lopez <mariano.lopez@linux.intel.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/lib/oeqa/oetest.py

@@ -385,6 +385,43 @@ class RuntimeTestContext(TestContext):
         if oeTest.hasPackage("procps"):
             oeRuntimeTest.pscmd = "ps -ef"
 
+    def _getJsonFile(self, module):
+        """
+        Returns the path of the JSON file for a module, empty if doesn't exitst.
+        """
+
+        module_file = module.filename
+        json_file = "%s.json" % module_file.rsplit(".", 1)[0]
+        if os.path.isfile(module_file) and os.path.isfile(json_file):
+            return json_file
+        else:
+            return ""
+
+    def _getNeededPackages(self, json_file, test=None):
+        """
+        Returns a dict with needed packages based on a JSON file.
+
+
+        If a test is specified it will return the dict just for that test.
+        """
+
+        import json
+
+        needed_packages = {}
+
+        with open(json_file) as f:
+            test_packages = json.load(f)
+        for key,value in test_packages.items():
+            needed_packages[key] = value
+
+        if test:
+            if test in needed_packages:
+                needed_packages = needed_packages[test]
+            else:
+                needed_packages = {}
+
+        return needed_packages
+
 class ImageTestContext(RuntimeTestContext):
     def __init__(self, d, target, host_dumper):
         super(ImageTestContext, self).__init__(d, target)