add initial makeComputaitonNode spec

Author: adamhaile

spec/S.makeComputationNode.spec.js

@@ -0,0 +1,30 @@
+describe("S.makeComputationNode()", () => S.root(() => {
+    it("returns null if function doesn't reference a signal", () => {
+        const { node, value } = S.makeComputationNode(() => 1, undefined, false, false);
+
+        expect(node).toBe(null);
+        expect(value).toBe(1);
+    });
+
+    it("returns a node if function does reference a signal", () => {
+        const
+            d = S.makeDataNode(1), 
+            { node, value } = S.makeComputationNode(() => d.current(), undefined, false, false);
+
+        expect(node).not.toBe(null);
+        expect(value).toBe(1);
+        expect(node.current()).toBe(1);
+    });
+
+    it("is listening", () => {
+        S.makeComputationNode(() => {
+            expect(S.isListening()).toBe(true);
+        })
+    });
+
+    it("is frozen", () => {
+        S.makeComputationNode(() => {
+            expect(S.isFrozen()).toBe(true);
+        })
+    });
+}));