feat(tests): update tests to use GBM for random data generation; improve consistency and realism in Skew and Variance tests; refine validation logic in Beta tests

.clinerules/MODELS.md

@@ -11,6 +11,12 @@ These tests verify the internal logic, state management, and API contract of the
 - **`Constructor_ValidatesInput`**: Verify that invalid parameters (e.g., `period <= 0`) throw `ArgumentException`.
 - **`Constructor_ValidatesOptionalArgs`**: If applicable, verify other parameters (e.g., `alpha`, `sigma`).
 
+### Random Data Generation
+
+- **Use `GBM` Helper**: Always use the `GBM` (Geometric Brownian Motion) helper class for generating random test data.
+- **Avoid `System.Random`**: Do not use `System.Random` directly in tests to ensure consistency and realism.
+- **Example**: `var gbm = new GBM(startPrice: 100, mu: 0.05, sigma: 0.2, seed: 123);`
+
 ### Basic Functionality
 
 - **`Calc_ReturnsValue`**: Verify `Update` returns a valid `TValue` and updates the `Last` property.

.github/workflows/Publish.yml

@@ -19,12 +19,7 @@ concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}
   cancel-in-progress: true
 
-permissions:
+permissions: {}
-  contents: write
-  pull-requests: read
-  security-events: write
-  checks: write
-  actions: read
 
 env:
   DOTNET_VERSION: '10.x'
@@ -37,6 +32,8 @@ jobs:
   # ==============================================================================
   Build_Test_Coverage:
     runs-on: ubuntu-latest
+    permissions:
+      contents: read
     steps:
       - name: Checkout repository
         uses: actions/checkout@v4
@@ -94,6 +91,8 @@ jobs:
   Sonar_Analysis:
     needs: Build_Test_Coverage
     runs-on: ubuntu-latest
+    permissions:
+      contents: read
     steps:
       - name: Checkout repository
         uses: actions/checkout@v4
@@ -167,6 +166,11 @@ jobs:
   Qodana_Scan:
     needs: Build_Test_Coverage
     runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      checks: write
+      security-events: write
+      pull-requests: read
     steps:
       - uses: actions/checkout@v4
         with:
@@ -191,6 +195,8 @@ jobs:
   Codacy_Upload:
     needs: Build_Test_Coverage
     runs-on: ubuntu-latest
+    permissions:
+      contents: read
     steps:
       - uses: actions/checkout@v4
         with:
@@ -230,6 +236,8 @@ jobs:
   # ==============================================================================
   Snyk_Scan:
     runs-on: ubuntu-latest
+    permissions:
+      contents: read
     steps:
       - uses: actions/checkout@v4
         with:
@@ -292,13 +300,12 @@ jobs:
   # ==============================================================================
   Publish_Package:
     needs: [Build_Test_Coverage, Sonar_Analysis, Qodana_Scan, Codacy_Upload, Snyk_Scan, CodeQL_Analysis]
-    if: |
+    if: >-
-      success() &&
+      (github.event_name == 'push' && (github.ref == 'refs/heads/main' || github.ref == 'refs/heads/dev' || endsWith(github.ref, '-dev'))) ||
-      (
+      github.event_name == 'workflow_dispatch'
-        (github.event_name == 'push' && (github.ref == 'refs/heads/main' || github.ref == 'refs/heads/dev' || endsWith(github.ref, '-dev'))) ||
-        github.event_name == 'workflow_dispatch'
-      )
     runs-on: ubuntu-latest
+    permissions:
+      contents: write
     steps:
       - uses: actions/checkout@v4
         with:

lib/statistics/beta/Beta.Validation.Tests.cs

@@ -93,7 +93,7 @@ public class BetaValidationTests : IDisposable
             double ql = qlBeta[i];
             
             // Skender might return null/0 for warmup.
-            if (sk != 0)
+            if (Math.Abs(sk) > 1e-10)
             {
                 Assert.Equal(sk, ql, ValidationHelper.DefaultTolerance);
             }

lib/statistics/skew/Skew.Tests.cs

@@ -176,11 +176,11 @@ public class SkewTests
     {
         // Run for > 1000 updates to trigger Resync
         var skew = new Skew(10);
-        var random = new Random(123);
+        var gbm = new GBM(startPrice: 100, mu: 0.05, sigma: 0.2, seed: 123);
         
         for (int i = 0; i < 1100; i++)
         {
-            skew.Update(new TValue(DateTime.UtcNow, random.NextDouble() * 100));
+            skew.Update(new TValue(DateTime.UtcNow, gbm.Next().Close));
         }
         
         Assert.True(double.IsFinite(skew.Last.Value));

lib/statistics/variance/Variance.Tests.cs

@@ -154,11 +154,11 @@ public class VarianceTests
     {
         // Run for > 1000 updates to trigger Resync
         var variance = new Variance(10);
-        var random = new Random(123);
+        var gbm = new GBM(startPrice: 100, mu: 0.05, sigma: 0.2, seed: 123);
         
         for (int i = 0; i < 1100; i++)
         {
-            variance.Update(new TValue(DateTime.UtcNow, random.NextDouble() * 100));
+            variance.Update(new TValue(DateTime.UtcNow, gbm.Next().Close));
         }
         
         Assert.True(double.IsFinite(variance.Last.Value));