test(rule): Add Observable.create fixture.

fixtures/observable-create/fixture.ts

@@ -0,0 +1,20 @@
+import { Observable } from "rxjs/Observable";
+import "rxjs/add/operator/filter";
+import "rxjs/add/operator/map";
+
+// Note that Observable.create is declared as a Function:
+// https://github.com/ReactiveX/rxjs/blob/5.3.1/src/Observable.ts#L46-L58
+//
+// So its result will be any - which will mess with the rules unless the
+// variable is explicitly typed:
+
+const ob1 = Observable.create((observer: Observer<number>) => {
+
+    observer.next(1);
+    observer.complete();
+});
+const ob2 = ob1.filter((value) => value > 1);
+
+
+const ob3 = ob1 as Observable<number>;
+const ob4 = ob3.map((value) => value + 1);

fixtures/observable-create/tsconfig.json

@@ -0,0 +1,13 @@
+{
+  "compilerOptions": {
+    "baseUrl": ".",
+    "lib": ["es2015"],
+    "noEmit": true,
+    "paths": {
+      "rxjs": ["../node_modules/rxjs"]
+    },
+    "skipLibCheck": true,
+    "target": "es5"
+  },
+  "include": ["fixture.ts"]
+}

source/fixtures-spec.ts

@@ -112,6 +112,17 @@ describe("fixtures", function (): void {
         });
     });
 
+    describe("observable-create", () => {
+
+        it("should effect an error unless explicit typing is used", () => {
+
+            const result = lint("observable-create");
+
+            expect(result).to.have.property("errorCount", 1);
+            expect(result.failures[0]).to.have.property("ruleName", "rxjs-no-unused-add");
+        });
+    });
+
     describe("unused-observable", () => {
 
         it("should effect 'rxjs-no-unused-add' errors", () => {