Fix Cycles::EndOf

CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [0.1.3] - Unreleased
 
+### Fixed
+
+- `Cycles::EndOf` to have the correct behavior
+
 ## [0.1.2] - 2024-08-09
 
 ### Added

lib/sof/cycles/end_of.rb

@@ -1,5 +1,13 @@
 # frozen_string_literal: true
 
+# Captures the logic for enforcing the EndOf cycle variant
+#   E.g. "V1E18MF2020-01-05" means:
+#     You're good until the end of the 17th subsequent month from 2020-01-05.
+#     Complete 1 by that date to reset the cycle.
+#
+# Some of the calculations are quite different from other cycles.
+# Whereas other cycles look at completion dates to determine if the cycle is
+# satisfied, this cycle checks whether the anchor date is prior to the final date.
 module SOF
   module Cycles
     class EndOf < Cycle
@@ -16,8 +24,34 @@ def to_s
         "#{volume}x by #{final_date.to_fs(:american)}"
       end
 
+      # Returns the expiration date for the cycle
+      #
+      # @param [nil] _ Unused parameter, maintained for compatibility
+      # @param anchor [nil] _ Unused parameter, maintained for compatibility
+      # @return [Date] The final date of the cycle
+      #
+      # @example
+      #   Cycle.for("V1E18MF2020-01-09")
+      #     .expiration_of(anchor: "2020-06-04".to_date)
+      #   # => #<Date: 2021-06-30>
+      def expiration_of(_ = nil, anchor: nil) = final_date
+
+      # Is the supplied anchor date prior to the final date?
+      #
+      # @return [Boolean] true if the cycle is satisfied, false otherwise
+      def satisfied_by?(_ = nil, anchor: Date.current) = anchor <= final_date
+
+      # Calculates the final date of the cycle
+      #
+      # @param [nil] _ Unused parameter, maintained for compatibility
+      # @return [Date] The final date of the cycle calculated as the end of the
+      #   nth subsequent period after the FROM date, where n = (period count - 1)
+      #
+      # @example
+      #   Cycle.for("V1E18MF2020-01-09").final_date
+      #   # => #<Date: 2021-06-30>
       def final_date(_ = nil) = time_span
-        .end_date(start_date)
+        .end_date(start_date - 1.send(period))
         .end_of_month
 
       def start_date(_ = nil) = from_date.to_date

spec/sof/cycles/end_of_spec.rb

@@ -10,24 +10,10 @@ module SOF
     let(:notation) { "V2E18MF#{from_date}" }
     let(:anchor) { nil }
 
-    let(:end_date) { (from_date.to_date + 18.months).end_of_month }
+    let(:end_date) { (from_date.to_date + 17.months).end_of_month }
     let(:from_date) { "2020-01-01" }
 
-    let(:completed_dates) do
-      [
-        recent_date,
-        middle_date,
-        early_date,
-        early_date,
-        too_early_date,
-        too_late_date
-      ]
-    end
-    let(:recent_date) { from_date.to_date + 17.months }
-    let(:middle_date) { from_date.to_date + 2.months }
-    let(:early_date) { from_date.to_date + 1.month }
-    let(:too_early_date) { from_date.to_date - 1.day }
-    let(:too_late_date) { end_date + 1.day }
+    let(:completed_dates) { [] }
 
     it_behaves_like "#kind returns", :end_of
     it_behaves_like "#valid_periods are", %w[W M Q Y]
@@ -38,7 +24,7 @@ module SOF
       end
     end
 
-    @end_date = ("2020-01-01".to_date + 18.months).end_of_month
+    @end_date = ("2020-01-01".to_date + 17.months).end_of_month
     it_behaves_like "#to_s returns",
       "2x by #{@end_date.to_fs(:american)}"
 
@@ -52,9 +38,26 @@ module SOF
     it_behaves_like "#notation returns the notation"
     it_behaves_like "#as_json returns the notation"
     it_behaves_like "it computes #final_date(given)",
-      given: nil, returns: ("2020-01-01".to_date + 18.months).end_of_month
+      given: nil, returns: ("2020-01-01".to_date + 17.months).end_of_month
 
     describe "#covered_dates" do
+      let(:completed_dates) do
+        [
+          recent_date,
+          middle_date,
+          early_date,
+          early_date,
+          too_early_date,
+          too_late_date
+        ]
+      end
+      let(:recent_date) { from_date.to_date + 17.months }
+      let(:middle_date) { from_date.to_date + 2.months }
+      let(:early_date) { from_date.to_date + 1.month }
+      let(:too_early_date) { from_date.to_date - 1.day }
+      let(:too_late_date) { end_date + 1.day }
+
+      let(:anchor) { "2021-06-29".to_date }
       it "given an anchor date, returns dates that fall within it's window" do
         expect(cycle.covered_dates(completed_dates, anchor:)).to eq([
           recent_date,
@@ -65,56 +68,54 @@ module SOF
       end
     end
 
-    describe "#satisfied_by?(completed_dates, anchor:)" do
-      context "when the completions--judged from the <from_date>--satisfy the cycle" do
+    describe "#satisfied_by?(anchor:)" do
+      context "when the anchor date is < the final date" do
+        let(:anchor) { "2021-06-29".to_date }
+
         it "returns true" do
-          expect(cycle).to be_satisfied_by(completed_dates, anchor:)
+          expect(cycle).to be_satisfied_by(anchor:)
         end
       end
 
-      context "when the completions are irrelevant to the given from_date" do
-        let(:completed_dates) do
-          [
-            10.years.ago,
-            Date.current,
-            10.years.from_now
-          ]
-        end
+      context "when the anchor date is = the final date" do
+        let(:anchor) { "2021-06-30".to_date }
 
-        it "returns false" do
-          expect(cycle).not_to be_satisfied_by(completed_dates, anchor:)
+        it "returns true" do
+          expect(cycle).to be_satisfied_by(anchor:)
         end
       end
 
-      context "when the completions currently do not satisfy the cycle" do
-        let(:notation) { "V5E18M" }
+      context "when the anchor date is > the final date" do
+        let(:anchor) { "2021-07-01".to_date }
 
         it "returns false" do
           expect(cycle).not_to be_satisfied_by(completed_dates, anchor:)
         end
       end
+    end
 
-      context "when there are no completions" do
-        let(:completed_dates) { [] }
+    describe "#expiration_of(completion_dates)" do
+      context "when the anchor date is < the final date" do
+        let(:anchor) { "2021-06-29".to_date }
 
-        it "returns false" do
-          expect(cycle).not_to be_satisfied_by(completed_dates, anchor:)
+        it "returns the final date" do
+          expect(cycle.expiration_of(anchor:)).to eq "2021-06-30".to_date
         end
       end
-    end
 
-    describe "#expiration_of(completion_dates)" do
-      context "when the completions currently satisfy the cycle" do
-        it "returns the date on which the completions will no longer satisfy the cycle" do
-          expect(cycle.expiration_of(completed_dates)).to be nil
+      context "when the anchor date = the final date" do
+        let(:anchor) { "2021-06-30".to_date }
+
+        it "returns the final date" do
+          expect(cycle.expiration_of(anchor:)).to eq "2021-06-30".to_date
         end
       end
 
-      context "when the completions currently do not satisfy the cycle" do
-        let(:notation) { "V5E18M" }
+      context "when the anchor date > the final date" do
+        let(:anchor) { "2021-07-31".to_date }
 
-        it "returns nil" do
-          expect(cycle.expiration_of(completed_dates)).to be_nil
+        it "returns the final date" do
+          expect(cycle.expiration_of(anchor:)).to eq "2021-06-30".to_date
         end
       end
     end