Add /xunit.analyzers/rules/xUnit1053

Author: bradwilson

site/xunit.analyzers/rules/xUnit1053.md

@@ -0,0 +1,72 @@
+---
+analyzer: true
+title: xUnit1053
+description: The static member used as theory data must be statically initialized
+category: Usage
+severity: Warning
+v2: true
+v3: true
+---
+
+## Cause
+
+A violation of this rule occurs when a member referenced by `[MemberData]` is not statically initialized.
+
+## Reason for rule
+
+Data provided by a member data source must be statically initialized so that it can be used to provide data for the tests that reference it with `[MemberData]`. Failing to initialize the data source will result in no data rows.
+
+## How to fix violations
+
+To fix a violation of this rule, either initialize the value inline or via a static constructor.
+
+## Examples
+
+### Violates
+
+```csharp
+using Xunit;
+
+public class xUnit1053
+{
+    public static TheoryData<int> DataSource;
+
+    [Theory]
+    [MemberData(nameof(DataSource))]
+    public void TestMethod(int x) =>
+        Assert.NotEqual(0, x);
+}
+```
+
+### Does not violate
+
+```csharp
+using Xunit;
+
+public class xUnit1053
+{
+    public static TheoryData<int> DataSource = [4, 9, 16];
+
+    [Theory]
+    [MemberData(nameof(DataSource))]
+    public void TestMethod(int x) =>
+        Assert.NotEqual(0, x);
+}
+```
+
+```csharp
+using Xunit;
+
+public class xUnit1053
+{
+    public static TheoryData<int> DataSource;
+
+    static xUnit1053() =>
+        DataSource = [4, 9, 16];
+
+    [Theory]
+    [MemberData(nameof(DataSource))]
+    public void TestMethod(int x) =>
+        Assert.NotEqual(0, x);
+}
+```