chore: add some documentation and somet testing

compat/getConfig.ts

@@ -1,4 +1,3 @@
-
 import { YAML } from "../dependencies.ts";
 import { matches } from "../dependencies.ts";
 import { ExpectedExports } from "../types.ts";
@@ -8,22 +7,31 @@ const { any, string, dictionary } = matches;
 
 const matchConfig = dictionary([string, any]);
 
-export const getConfig = (spec: ConfigSpec): ExpectedExports.getConfig => async (effects) => {
+/**
+ * Call with the configuration to get a standard getConfig for the expected exports
+ * Assumption: start9/config.yaml is where the config will be stored
+ * Throws: Error if there is no file
+ * Throws: Error if the config.yaml isn't yaml nor config shape 
+ * @param spec
+ * @returns
+ */
+export const getConfig = (spec: ConfigSpec): ExpectedExports.getConfig =>
+  async (effects) => {
     const config = await effects
-        .readFile({
-            path: "start9/config.yaml",
-            volumeId: "main",
-        })
-        .then((x) => YAML.parse(x))
-        .then((x) => matchConfig.unsafeCast(x))
-        .catch((e) => {
-            effects.info(`Got error ${e} while trying to read the config`);
-            return undefined;
-        });
+      .readFile({
+        path: "start9/config.yaml",
+        volumeId: "main",
+      })
+      .then((x) => YAML.parse(x))
+      .then((x) => matchConfig.unsafeCast(x))
+      .catch((e) => {
+        effects.info(`Got error ${e} while trying to read the config`);
+        return undefined;
+      });
     return {
-        result: {
-            config,
-            spec,
-        },
+      result: {
+        config,
+        spec,
+      },
     };
-};
+  };