DataSeries.Copy

Src/Myc.Test.Trade.DataPoint.pas

@@ -95,6 +95,14 @@ type
         procedure TestIndexOfSingleItemSeries;
         [Test]
         procedure TestIndexOfRespectsMaxLookback;
+
+        // Tests for Copy
+        [Test]
+        procedure TestCopyHasSameContent;
+        [Test]
+        procedure TestCopyIsImmutableAfterOriginalChanges;
+        [Test]
+        procedure TestCopyRespectsMaxLookback;
     end;
 
 implementation
@@ -403,7 +411,7 @@ end;
 procedure TTestDataSeries.Setup;
 begin
     FArray := TDataSeries<TAskBidItem>.CreateArray(0);
-    FSeries.Create(FArray);
+    FSeries := FArray;
 end;
 
 procedure TTestDataSeries.Teardown;
@@ -419,7 +427,7 @@ var
     baseTime: TDateTime;
 begin
     FArray := TDataSeries<TAskBidItem>.CreateArray(MaxLookBack);
-    FSeries.Create(FArray);
+    FSeries := FArray;
     baseTime := EncodeDate(2020, 7, 7);
 
     // Add data points with increasing timestamps.
@@ -430,6 +438,79 @@ begin
     end;
 end;
 
+procedure TTestDataSeries.TestCopyHasSameContent;
+var
+    copy: TDataSeries<TAskBidItem>;
+    i: Integer;
+begin
+    SetupSeriesWithData(15);
+
+    copy := FSeries.Copy;
+
+    Assert.AreEqual(FSeries.Count, copy.Count, 'Copy must have the same count as the original');
+    Assert.AreEqual(FSeries.TotalCount, copy.TotalCount, 'Copy must have the same total count as the original');
+
+    for i := 0 to FSeries.Count - 1 do
+    begin
+        Assert.AreEqual(FSeries[i].Time, copy[i].Time, 'Copied item timestamp must match original');
+        Assert.AreEqual(FSeries[i].Data.Ask, copy[i].Data.Ask, 'Copied item data must match original');
+    end;
+end;
+
+procedure TTestDataSeries.TestCopyIsImmutableAfterOriginalChanges;
+var
+    copy: TDataSeries<TAskBidItem>;
+    originalCount, originalTotalCount: Int64;
+    newPoint: TDataPoint<TAskBidItem>;
+    lastTime: TDateTime;
+begin
+    SetupSeriesWithData(10);
+
+    // Create the copy
+    copy := FSeries.Copy;
+    originalCount := copy.Count;
+    originalTotalCount := copy.TotalCount;
+
+    // Modify the original series
+    lastTime := FArray[0].Time;
+    newPoint := TDataPoint<TAskBidItem>.Create(lastTime + 1, TAskBidItem.Create(99, 99.1));
+    FArray.Add(newPoint);
+
+    Assert.AreEqual(Int64(11), FArray.Count, 'Original array count should have increased');
+
+    // Verify the copy remains unchanged
+    Assert.AreEqual(originalCount, copy.Count, 'Copy count must not change after original is modified');
+    Assert.AreEqual(originalTotalCount, copy.TotalCount, 'Copy total count must not change after original is modified');
+    Assert.AreNotEqual(FArray[0].Time, copy[0].Time, 'Newest item in copy should not be the new item from original');
+end;
+
+procedure TTestDataSeries.TestCopyRespectsMaxLookback;
+var
+    copy: TDataSeries<TAskBidItem>;
+    newPoint: TDataPoint<TAskBidItem>;
+    lastTime: TDateTime;
+begin
+    SetupSeriesWithData(20, 15); // 20 items total, but series count is capped at 15
+
+    Assert.AreEqual(Int64(15), FSeries.Count, 'Pre-condition: Series count should be capped by MaxLookback');
+    Assert.AreEqual(Int64(20), FSeries.TotalCount, 'Pre-condition: Series total count should be 20');
+
+    copy := FSeries.Copy;
+
+    // Verify the copy reflects the MaxLookback state
+    Assert.AreEqual(Int64(15), copy.Count, 'Copy count should be the MaxLookback value of the original');
+    Assert.AreEqual(Int64(20), copy.TotalCount, 'Copy total count should be the total items added to the original');
+
+    // Modify original
+    lastTime := FArray[0].Time;
+    newPoint := TDataPoint<TAskBidItem>.Create(lastTime + 1, TAskBidItem.Create(99, 99.1));
+    FArray.Add(newPoint);
+
+    // Verify the copy is still unchanged
+    Assert.AreEqual(Int64(15), copy.Count, 'Copy count must remain unchanged after original is modified');
+    Assert.AreEqual(Int64(20), copy.TotalCount, 'Copy total count must remain unchanged after original is modified');
+end;
+
 procedure TTestDataSeries.TestIndexOfExistingTimeStamp;
 var
     ATimeStamp: TDateTime;