Fix pouchEffectsLedger; update tests

.gitignore

@@ -1,3 +1,4 @@
 node_modules
 .DS_Store
 *.log
+coverage

package.json

@@ -18,5 +18,10 @@
   "devDependencies": {
     "documentation": "^5.3.3",
     "jest": "^21.2.1"
+  },
+  "jest": {
+    "collectCoverage": true,
+    "coverageDirectory": "<rootDir>/coverage",
+    "coveragePathIgnorePatterns": ["/node_modules/", "/templates/", "/dist/"]
   }
 }

src/index.js

@@ -159,7 +159,7 @@ const totalOf = (currency, ...ledgers) => {
  * @param {Object} state a state object that will be passed to the cost to determine the type
  */
 const buy = (item, wallet, state = {}) => {
-  if (!item.cost) {
+  if (!item || !item.cost) {
     return wallet;
   }
 
@@ -204,9 +204,12 @@ const addItem = (item, wallet, amount = 1) => {
  * @param {Object} state
  */
 const pouchEffectsLedger = (items, wallet, state = {}) => {
-  const ledgers = items.map(item => {
-    return scale(item.effect(state), maybe(wallet.get(item.type), 0));
-  });
+  const ledgers = items
+    .map(item => {
+      if (!item.effect) return;
+      return scale(item.effect(state), maybe(wallet.get(item.type), 0));
+    })
+    .filter(n => n);
   return add(...ledgers);
 };
 

src/test/merchant.test.js

@@ -121,6 +121,10 @@ describe("currencies", () => {
     expect(() => currencies({ notA: "ledger" })).toThrow();
   });
 
+  test("currencies returns a list even if nothing is defined", () => {
+    expect(List.isList(currencies())).toBe(true);
+  });
+
   test("currencies returns a list", () => {
     const result = currencies(Map({ GOLD: "5" }));
     expect(List.isList(result)).toBe(true);
@@ -142,6 +146,10 @@ describe("totalOf", () => {
     expect(() => totalOf("HAHAHA", { NOTA: "ledger" })).toThrow();
   });
 
+  test("totalOf will give you 0 if nothing is defined", () => {
+    expect(totalOf()).toBe(0);
+  });
+
   test("totalOf will give you 0 if the currency doesn't exist", () => {
     const one = Map({ GOLD: 5 });
     const two = Map({ SILVER: 5 });
@@ -164,6 +172,11 @@ describe("buy", () => {
       })
   };
 
+  test("buy will return the same wallet if nothing is defined", () => {
+    const wallet = Map({ Foo: 5 });
+    expect(buy(null, wallet)).toBe(wallet);
+  });
+
   test("buy will throw if it receives an item with a cost attribute that's not a function", () => {
     expect(() => buy({ cost: "ya", type: "ha" })).toThrow();
   });
@@ -201,6 +214,19 @@ describe("pouchEffectsLedger", () => {
     expect(pouchEffectsLedger([], Map({})).size).toBe(0);
   });
 
+  test("pouchEffectsLedger returns an empty ledger if there are no items with 'effects'", () => {
+    const MagicSword = {
+      type: "MagicSword"
+    };
+
+    const ledger = pouchEffectsLedger(
+      [MagicSword],
+      Map({ MagicSword: 2, Charm: 1 })
+    );
+
+    expect(ledger.size).toBe(0);
+  });
+
   test("pouchEffectsLedger returns a ledger with a combination of effects", () => {
     const MagicSword = {
       type: "MagicSword",