Add directory functionality (#181)

src/utilities/fileUtils.test.ts

@@ -0,0 +1,49 @@
+import {
+  getFilesFromDirectories
+  } from "./fileUtils";
+  
+  import * as path from "path";
+
+  describe("File utils", () => {
+    it("detects files in nested directories and ignores non-manifest files and empty dirs", () => {
+      const testPath = path.join("test", "unit", "manifests")
+      const testSearch: string[] = getFilesFromDirectories([testPath])
+
+      const expectedManifests = 
+        [
+            "test/unit/manifests/manifest_test_dir/another_layer/deep-ingress.yaml",
+            "test/unit/manifests/manifest_test_dir/another_layer/deep-service.yaml",
+            "test/unit/manifests/manifest_test_dir/nested-test-service.yaml",
+            "test/unit/manifests/test-ingress.yml",
+            "test/unit/manifests/test-service.yml"
+        ]
+      
+    
+        // is there a more efficient way to test equality w random order?
+      expect(testSearch).toHaveLength(5);
+      expectedManifests.forEach((fileName) => {
+          expect(testSearch).toContain(fileName)
+      })
+
+    });
+
+    it("crashes when an invalid file is provided", () => {
+        const badPath = path.join("test", "unit", "manifests", "nonexistent.yaml")
+        const goodPath = path.join("test", "unit", "manifests", "manifest_test_dir")
+
+        expect(() => {getFilesFromDirectories([badPath, goodPath])}).toThrowError()
+    });
+
+    it("doesn't duplicate files when nested dir included", () => {
+        const outerPath = path.join("test", "unit", "manifests")
+        const fileAtOuter = path.join("test", "unit", "manifests", "test-service.yml")
+        const innerPath = path.join("test", "unit", "manifests", "manifest_test_dir")
+
+        expect(getFilesFromDirectories([outerPath, fileAtOuter, innerPath])).toHaveLength(5)
+    })
+  });
+
+  
+  // files that don't exist / nested files that don't exist / something else with non-manifest
+  // lots of combinations of pointing to a directory and non yaml/yaml file
+  // similarly named files in different folders