Add returns and charts slice (3d-9b)

1 files changed, 47 insertions, 0 deletions

diff --git a/tests/FundLab.Web.Tests/ChartTests.fs b/tests/FundLab.Web.Tests/ChartTests.fs
index cede2d2..0382b0a 100644
--- a/tests/FundLab.Web.Tests/ChartTests.fs
+++ b/tests/FundLab.Web.Tests/ChartTests.fs
@@ -21,3 +21,50 @@ module ChartTests =
         Assert.Equal(1.0, points[1].y)
         Assert.Equal(0.4, points[2].y)
         Assert.Equal("2026-01-03", points[2].navDate)
+
+    [<Fact>]
+    let ``series points keep the shared date axis and normalize each series`` () =
+        let dates = [ "2026-01-01"; "2026-01-02"; "2026-01-03" ]
+
+        let values =
+            [
+                "2026-01-01", "100.00"
+                "2026-01-02", "150.00"
+                "2026-01-03", "125.00"
+            ]
+
+        let points = Chart.seriesPoints dates values
+
+        Assert.Equal(3, points.Length)
+        Assert.Equal(0.0, points[0].x)
+        Assert.Equal(0.5, points[1].x)
+        Assert.Equal(1.0, points[2].x)
+        Assert.Equal(0.0, points[0].y)
+        Assert.Equal(1.0, points[1].y)
+        Assert.Equal(0.5, points[2].y)
+        Assert.Equal("150.00", points[1].value)
+
+    [<Fact>]
+    let ``series points skip missing dates instead of filling zero`` () =
+        let dates = [ "2026-01-01"; "2026-01-02"; "2026-01-03" ]
+
+        let values =
+            [
+                "2026-01-01", "100.00"
+                "2026-01-03", "125.00"
+            ]
+
+        let points = Chart.seriesPoints dates values
+
+        Assert.Equal(2, points.Length)
+        Assert.Equal(0.0, points[0].x)
+        Assert.Equal(1.0, points[1].x)
+        Assert.Equal("2026-01-03", points[1].label)
+
+    [<Fact>]
+    let ``a single point is centered and keeps no line`` () =
+        let points = Chart.seriesPoints [ "2026-01-01" ] [ "2026-01-01", "1.00000000" ]
+
+        Assert.Equal(1, points.Length)
+        Assert.Equal(0.5, points[0].x)
+        Assert.Equal(0.5, points[0].y)