feat: throw PriceNotFound when number of subscriptions is invalid

Author: adrianliz

exercises/tiered_pricing/solutions/adrianliz/java/src/main/java/tv/codely/checkout/PriceNotFound.java

@@ -0,0 +1,8 @@
+package tv.codely.checkout;
+
+public final class PriceNotFound extends RuntimeException {
+
+    public PriceNotFound(int subscriptions) {
+        super(String.format("Price not found for %d subscriptions", subscriptions));
+    }
+}

exercises/tiered_pricing/solutions/adrianliz/java/src/main/java/tv/codely/checkout/SubscriptionTier.java

@@ -23,10 +23,6 @@ public boolean isLast() {
         return range.isLast();
     }
 
-    public boolean isAfter(final SubscriptionTier other) {
-        return range.isAfter(other.range);
-    }
-
     public boolean isInRange(int numberOfSubscriptions) {
         return this.range.isSuitableFor(numberOfSubscriptions);
     }

exercises/tiered_pricing/solutions/adrianliz/java/src/main/java/tv/codely/checkout/SubscriptionTierRange.java

@@ -63,10 +63,6 @@ public boolean isLast() {
         return numberOfSubscriptionsTo == Integer.MAX_VALUE;
     }
 
-    public boolean isAfter(final SubscriptionTierRange other) {
-        return numberOfSubscriptionsFrom > other.numberOfSubscriptionsTo;
-    }
-
     public boolean isSuitableFor(int numberOfSubscriptions) {
         return numberOfSubscriptions >= numberOfSubscriptionsFrom
             && numberOfSubscriptions <= numberOfSubscriptionsTo;

exercises/tiered_pricing/solutions/adrianliz/java/src/main/java/tv/codely/checkout/SubscriptionTiers.java

@@ -1,17 +1,17 @@
 package tv.codely.checkout;
 
-import java.util.List;
+import java.util.Set;
 
 public final class SubscriptionTiers {
 
-    private final List<SubscriptionTier> tiers;
+    private final Set<SubscriptionTier> tiers;
 
-    public SubscriptionTiers(List<SubscriptionTier> tiers) {
+    public SubscriptionTiers(final Set<SubscriptionTier> tiers) {
         validate(tiers);
         this.tiers = tiers;
     }
 
-    private static void validate(final List<SubscriptionTier> tiers) {
+    private static void validate(final Set<SubscriptionTier> tiers) {
         if (tiers == null || tiers.isEmpty()) {
             throw new InvalidSubscriptionTiers("There must be at least one subscription tier");
         }
@@ -25,19 +25,18 @@ private static void validate(final List<SubscriptionTier> tiers) {
         }
     }
 
-    private SubscriptionTier findSuitableTier(int subscriptions) {
+    private SubscriptionTier findSuitableTier(int numberOfSubscriptions) {
         return tiers.stream()
-            .filter(tier -> tier.isInRange(subscriptions))
+            .filter(tier -> tier.isInRange(numberOfSubscriptions))
             .findFirst()
-            .orElseThrow(() -> new InvalidSubscriptionTiers(
-                "There is no subscription tier for " + subscriptions + " subscriptions"));
+            .orElseThrow(() -> new PriceNotFound(numberOfSubscriptions));
     }
 
-    public double getTotalPrice(int subscriptions) {
-        return findSuitableTier(subscriptions).getTotalPrice(subscriptions);
+    public double getTotalPrice(int numberOfSubscriptions) {
+        return findSuitableTier(numberOfSubscriptions).getTotalPrice(numberOfSubscriptions);
     }
 
-    public double getBasePrice(int subscriptions) {
-        return findSuitableTier(subscriptions).unitPrice();
+    public double getBasePrice(int numberOfSubscriptions) {
+        return findSuitableTier(numberOfSubscriptions).unitPrice();
     }
 }

exercises/tiered_pricing/solutions/adrianliz/java/src/main/java/tv/codely/checkout/TieredPricing.java

@@ -1,24 +1,24 @@
 package tv.codely.checkout;
 
-import java.util.List;
+import java.util.Set;
 
 public class TieredPricing {
-    
+
     private final SubscriptionTiers tiers;
 
     public TieredPricing(final SubscriptionTiers subscriptionTiers) {
         this.tiers = subscriptionTiers;
     }
 
-    public TieredPricing(final List<SubscriptionTier> subscriptionTiers) {
+    public TieredPricing(final Set<SubscriptionTier> subscriptionTiers) {
         this(new SubscriptionTiers(subscriptionTiers));
     }
 
-    public double getTotalPrice(int subscriptions) {
-        return tiers.getTotalPrice(subscriptions);
+    public double getTotalPrice(int numberOfSubscriptions) {
+        return tiers.getTotalPrice(numberOfSubscriptions);
     }
 
-    public double getBasePrice(int subscriptions) {
-        return tiers.getBasePrice(subscriptions);
+    public double getBasePrice(int numberOfSubscriptions) {
+        return tiers.getBasePrice(numberOfSubscriptions);
     }
 }

exercises/tiered_pricing/solutions/adrianliz/java/src/test/java/tv/codely/checkout/TieredPricingShould.java

@@ -1,11 +1,10 @@
 package tv.codely.checkout;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.util.List;
+import java.util.Set;
 import org.junit.jupiter.api.Test;
 import tv.codely.checkout.mother.IntegerMother;
 import tv.codely.checkout.mother.SubscriptionTierMother;
@@ -14,13 +13,13 @@
 
 public class TieredPricingShould {
 
-    private static List<SubscriptionTier> defaultSubscriptionTiers() {
+    private static Set<SubscriptionTier> defaultSubscriptionTiers() {
         final var firstTierRange = SubscriptionTierRange.first(2);
         final var secondTierRange = SubscriptionTierRange.from(firstTierRange, 7);
         final var thirdTierRange = SubscriptionTierRange.from(secondTierRange, 14);
         final var fourthTierRange = SubscriptionTierRange.from(thirdTierRange, 24);
         final var lastTierRange = SubscriptionTierRange.last(fourthTierRange);
-        return List.of(
+        return Set.of(
             new SubscriptionTier(
                 firstTierRange,
                 new SubscriptionTierPrice(299)),
@@ -56,18 +55,6 @@ void return_total_price_based_on_number_of_subscriptions() {
         assertEquals(expectedPrice, totalPrice);
     }
 
-    @Test
-    void should_have_a_subscription_tier_range_with_no_upper_limit() {
-        final var subscriptionTiers = SubscriptionTierMother.randoms();
-        final var lastSubscriptionTier =
-            subscriptionTiers.stream()
-                .filter(SubscriptionTier::isLast)
-                .findFirst()
-                .orElse(null);
-
-        assertNotNull(lastSubscriptionTier);
-    }
-
     @Test
     void return_total_price_for_1_subscription() {
         final var tieredPricing = new TieredPricing(defaultSubscriptionTiers());
@@ -115,15 +102,31 @@ void return_total_price_for_51_subscriptions() {
 
     @Test
     void throw_invalid_subscription_tiers_if_there_is_no_tiers() {
-        assertThrows(InvalidSubscriptionTiers.class, () -> new TieredPricing(List.of()));
+        assertThrows(InvalidSubscriptionTiers.class, () -> new TieredPricing(Set.of()));
     }
 
     @Test
     void throw_invalid_subscription_tiers_if_there_is_no_last_tier() {
         final var subscriptionTiers =
-            List.of(SubscriptionTierMother.create(SubscriptionTierRangeMother.first(10),
+            Set.of(SubscriptionTierMother.create(SubscriptionTierRangeMother.first(10),
                 SubscriptionTierPriceMother.random()));
 
         assertThrows(InvalidSubscriptionTiers.class, () -> new TieredPricing(subscriptionTiers));
     }
+
+    @Test
+    void throw_invalid_subscription_tier_range_if_number_of_susbcriptions_is_less_than_1() {
+        assertThrows(InvalidSubscriptionTierRange.class, () -> SubscriptionTierRange.first(0));
+    }
+
+    @Test
+    void throw_invalid_subscription_tier_range_if_previous_range_does_not_exist() {
+        assertThrows(InvalidSubscriptionTierRange.class, () -> SubscriptionTierRange.last(null));
+    }
+
+    @Test
+    void throw_price_not_found_if_number_of_subscriptions_is_not_valid() {
+        final var tieredPricing = new TieredPricing(defaultSubscriptionTiers());
+        assertThrows(PriceNotFound.class, () -> tieredPricing.getTotalPrice(0));
+    }
 }

exercises/tiered_pricing/solutions/adrianliz/java/src/test/java/tv/codely/checkout/mother/SubscriptionTierMother.java

@@ -1,7 +1,8 @@
 package tv.codely.checkout.mother;
 
-import java.util.List;
+import java.util.Set;
 import java.util.concurrent.atomic.AtomicReference;
+import java.util.stream.Collectors;
 import tv.codely.checkout.SubscriptionTier;
 import tv.codely.checkout.SubscriptionTierPrice;
 import tv.codely.checkout.SubscriptionTierRange;
@@ -15,7 +16,7 @@ public static SubscriptionTier create(
         return new SubscriptionTier(range, price);
     }
 
-    public static List<SubscriptionTier> randoms() {
+    public static Set<SubscriptionTier> randoms() {
         final var subscriptionTierRanges = SubscriptionTierRangeMother.randoms();
         final var previousSubscriptionTierPrice = new AtomicReference<>(299D);
 
@@ -28,6 +29,6 @@ public static List<SubscriptionTier> randoms() {
                 previousSubscriptionTierPrice.set(subscriptionTierPrice);
                 return create(range, SubscriptionTierPriceMother.create(subscriptionTierPrice));
             })
-            .toList();
+            .collect(Collectors.toSet());
     }
 }