Cargo selection planning now works.

test/the_great_game/merchants/merchants_test.clj

@@ -21,3 +21,89 @@
       (let [actual (expected-price (-> world :merchants :archie) :iron :buckie)
             expected 1.7] ;;
         (is (= actual expected) "if information select the most recent")))))
+
+(deftest plan-trade-test
+  (testing "Lower level trade planning"
+    (let [world (deep-merge
+                  default-world
+                  {:merchants
+                   {:fiona
+                    {:known-prices
+                     {:aberdeen
+                      {:iron
+                       [{:price 1.5 :date 1}
+                        {:price 1.3 :date 0}]}
+                      :buckie
+                      {:iron
+                       [{:price 1.7 :date 1}
+                        {:price 2 :date 0}]}}}}
+                   :cities
+                   {:falkirk
+                    {:stock {:iron 20}}}})
+          actual (plan-trade :fiona world :iron)]
+      (is (= (:origin actual) :falkirk)
+          "Fiona is in Falkirk, so her plan must originate there")
+      (is (= (:commodity actual) :iron)
+          "Iron is the only thing available in Falkirk, so plan must carry iron")
+      (is (= (:destination actual) :buckie)
+          "Fiona believes Buckie offers the best price for iron, so should go there"))))
+
+
+(deftest select-cargo-test
+  (testing "Top level single trade planning: single candidate commodity"
+    (let [world (deep-merge
+                  default-world
+                  {:merchants
+                   {:fiona
+                    {:known-prices
+                     {:aberdeen
+                      {:iron
+                       [{:price 1.5 :date 1}
+                        {:price 1.3 :date 0}]}
+                      :buckie
+                      {:iron
+                       [{:price 1.7 :date 1}
+                        {:price 2 :date 0}]}}}}
+                   :cities
+                   {:falkirk
+                    {:stock {:iron 20}}}})
+          actual (select-cargo :fiona world)]
+      (is (= (:origin actual) :falkirk)
+          "Fiona is in Falkirk, so her plan must originate there")
+      (is (= (:commodity actual) :iron)
+          "Iron is the only thing available in Falkirk, so plan must carry iron")
+      (is (= (:destination actual) :buckie)
+          "Fiona believes Buckie offers the best price for iron, so should go there")
+      (is (= (:quantity actual) 1)
+          "Fiona can carry only one unit of iron.")
+      (is (= (:expected-profit actual) 0.7))))
+  (testing "Top level single trade planning: multiple candidate commodities"
+    (let [world (deep-merge
+                  default-world
+                  {:merchants
+                   {:fiona
+                    {:known-prices
+                     {:aberdeen
+                      {:iron
+                       [{:price 1.5 :date 1}
+                        {:price 1.3 :date 0}]
+                       :whisky [{:price 4 :date 0}]}
+                      :buckie
+                      {:iron
+                       [{:price 1.7 :date 1}
+                        {:price 2 :date 0}]}}}}
+                   :cities
+                   {:falkirk
+                    {:stock
+                     {:iron 20
+                      :whisky 50}}}})
+          actual (select-cargo :fiona world)]
+      (is (= (:origin actual) :falkirk)
+          "Fiona is in Falkirk, so her plan must originate there")
+      (is (= (:commodity actual) :whisky)
+          "Whisky has the higher profit, so plan must carry whisky")
+      (is (= (:destination actual) :aberdeen)
+          "Fiona believes Aberdeen offers the best price for whisky, so should go there")
+      (is (= (:quantity actual) 50)
+          "Fiona can carry 100 units of whisky, but only 50 are available.")
+      (is (= (:expected-profit actual) 150)))))