Test crashes when view contains Swift Charts

[hiragram]

Describe the bug
Test crashes view.layer.render(in: ctx.cgContext) when view contains Swift Charts

To Reproduce
Minimum reproduction code is TBD.

❌ Crashed

            Chart(data ?? [], id: \.date) { entry in
                AreaMark(
                    x: .value("Date", entry.date),
                    y: .value("Count", entry.count)
                )
                .foregroundStyle(.linearGradient(.init(colors: [.key.opacity(0.4), .key.opacity(0.05)]), startPoint: .top, endPoint: .bottom))
                .interpolationMethod(interpolationMethod)

                LineMark(
                    x: .value("Date", entry.date),
                    y: .value("Count", entry.count)
                )
                .lineStyle(.init(lineWidth: 2))
                .foregroundStyle(Color.key)
                .symbol {
                    Circle()
                        .foregroundColor(.key)
                        .frame(width: 8)
                        .overlay {
                            Circle()
                                .padding(2)
                                .foregroundColor(.background)
                        }
                }
                .interpolationMethod(interpolationMethod)
            }
            .frame(height: 200)
            .chartXAxis(.visible)
            .chartYAxis(.visible)
            .chartYScale(domain: 0 ... yAxisMax)
            .chartXAxis {
                AxisMarks(values: .stride(by: .day)) { value in
                    if value.index % (value.count / 3) == 0 {
                        AxisGridLine()
                        AxisValueLabel()
                    } else {
                        AxisGridLine()
                    }
                }
            }
            .chartOverlay { chartProxy in
                GeometryReader { geometry in
                    Rectangle().fill(.clear).contentShape(Rectangle())
                        .gesture(
                            DragGesture(minimumDistance: 0)
                                .onChanged({ value in
                                    let currentX = value.location.x - geometry[chartProxy.plotAreaFrame].origin.x
                                    if let currentDate: Date = chartProxy.value(atX: currentX) {
                                        presenter.setSelectedDate(date: currentDate)
                                    }
                                })
                        )
                }
            }

❌ Crashed even if all modifiers of Chart are removed

            Chart(data ?? [], id: \.date) { entry in
                AreaMark(
                    x: .value("Date", entry.date),
                    y: .value("Count", entry.count)
                )
                .foregroundStyle(.linearGradient(.init(colors: [.key.opacity(0.4), .key.opacity(0.05)]), startPoint: .top, endPoint: .bottom))
                .interpolationMethod(interpolationMethod)

                LineMark(
                    x: .value("Date", entry.date),
                    y: .value("Count", entry.count)
                )
                .lineStyle(.init(lineWidth: 2))
                .foregroundStyle(Color.key)
                .symbol {
                    Circle()
                        .foregroundColor(.key)
                        .frame(width: 8)
                        .overlay {
                            Circle()
                                .padding(2)
                                .foregroundColor(.background)
                        }
                }
                .interpolationMethod(interpolationMethod)
            }

❌ Crashed even if all modifiers of XXXMarks are removed.

            Chart(data ?? [], id: \.date) { entry in
                AreaMark(
                    x: .value("Date", entry.date),
                    y: .value("Count", entry.count)
                )

                LineMark(
                    x: .value("Date", entry.date),
                    y: .value("Count", entry.count)
                )
            }

✅ Did not crash if Chart contains no XXXMark

            Chart(data ?? [], id: \.date) { entry in

            }

Expected behavior
No crash

Environment

• swift-snapshot-testing version [e.g. 1.9.0]: 1.10.0, 1.13.0, latest main(d1082c48edaee17914556517b29cea7e3388b2b7)
• Xcode [e.g. 13.2]: 13.4.1
• Swift [e.g. 5.5]:
• OS: [e.g. iOS 15]: iOS 16.4, iPhone 14 Pro simulator

Additional context
Add any more context about the problem here.

[mbrandonw]

Hi @hiragram, I am going to convert this to a discussion because it is not clear that it is actually a problem with the library that we could possible fix. It seems to be a problem with the Charts framework.

[ZevEisenberg]

Came here to +1 this. I tried standalone and hosted tests, iOS 17.

[ZevEisenberg]

Ooh, but I was able to make it work by running a hosted test and using drawHierarchyInKeyWindow: true!

[junebash]

@mbrandonw Are you or Stephen aware of anyone finding any other workaround(s) for this issue? I managed to create my own strategy using ImageRenderer but it's not without its own issues (doesn't render segmented controls, for one...). I see the above hosted-test-in-key-window workaround but would prefer to avoid that as well as we have SPM package test targets that can't seem to run in a hosted app environment.

[mbrandonw]

Hi @junebash, sorry we've never used the Charts framework and don't know of a workaround.

[BilalSaifudeen]

I am facing the same with Views containing charts and narrowed down a bit more.

✅ The follow simple chart with data [1, 2, 3, 4, 5] works

@Test func testChartSnapshotSmallValue() async throws {
   let dataPoints = [1, 2, 3, 4, 5]
   let view = Chart {
       ForEach(dataPoints, id: \.self) { dataPoint in
           LineMark(x: .value("X", dataPoint),
                    y: .value("Y", dataPoint))
       }
   }
       .frame(width: 200, height: 200)
   
   assertSnapshot(of: view)
}

❌ But, when the data is changed to [10, 20, 30, 40, 50], it crashes.

@Test func testChartSnapshotBiggerValue() async throws {
   let dataPoints = [10, 20, 30, 40, 50]
   let view = Chart {
       ForEach(dataPoints, id: \.self) { dataPoint in
           LineMark(x: .value("X", dataPoint),
                    y: .value("Y", dataPoint))
       }
   }
       .frame(width: 200, height: 200)
   
   assertSnapshot(of: view)
}

❌ As mentioned here, it crashes for me as well

@Test func testRectangleWithShadow() async throws {
    let view = Rectangle()
        .fill(Color.red.shadow(.inner(color: Color.black, radius: 6, x: 0, y: 0)))
    
    assertSnapshot(of: view, as: .image)
}

I have tests in frameworks for which I don't want to use hosted app for tests.
The ImageRender didn't work for me, it had a timeout failure.

Any other solution? @stephencelis @mbrandonw

[mbrandonw]

Hi @BilalSaifudeen, sorry but we don't know of any workarounds for this issue.