Allow null oilLevel and confidence in CLOEResult

The cloe analyzer now emits null for oilLevel and confidence when
the prediction confidence is below threshold. Loosen the DTO to
float? and guard the MQTT projection so low-confidence results
publish null Value/Confidence instead of throwing on deserialize.

Author: aeshub

api.Tests/Services/ResultHandlers/WorkflowResultHandlers/CLOEResultHandlerTests.cs

@@ -130,4 +130,59 @@ public async Task OnWorkflowCompleted_NullResultJson_PublishesMessageWithNullVal
         Assert.Null(published.Value);
         Assert.Null(published.Confidence);
     }
+
+    [Fact]
+    public async Task OnWorkflowCompleted_LowConfidenceResultWithNullFields_PublishesNullValueAndConfidence()
+    {
+        var record = await _db.NewInspectionRecord(inspectionId: "insp-123");
+        var analysis = await _db.NewAnalysis(inspectionRecords: [record]);
+        var run = await _db.NewAnalysisRun(analysis);
+        var workflow = await _db.NewWorkflow(run, workflowType: "cloe");
+        workflow.ResultJson = JsonSerializer.Serialize(
+            new { oilLevel = (float?)null, confidence = (float?)null }
+        );
+        await _context.SaveChangesAsync(TestContext.Current.CancellationToken);
+
+        using var scope = _factory.Services.CreateScope();
+        var handler = ResolveHandler(scope);
+
+        await handler.OnWorkflowCompleted(workflow);
+
+        var published = Assert.Single(_factory.MqttPublisher.AnalysisResultMessages);
+        Assert.Null(published.Value);
+        Assert.Null(published.Confidence);
+        Assert.Null(published.Warning);
+    }
+
+    [Fact]
+    public async Task OnWorkflowCompleted_ResultWithWarning_PublishesWarning()
+    {
+        const float oilLevel = 0.02f;
+        const float confidence = 0.80f;
+        const string warning = "Oil level is below 5 %";
+
+        var record = await _db.NewInspectionRecord(inspectionId: "insp-123");
+        var analysis = await _db.NewAnalysis(inspectionRecords: [record]);
+        var run = await _db.NewAnalysisRun(analysis);
+        var workflow = await _db.NewWorkflow(run, workflowType: "cloe");
+        workflow.ResultJson = JsonSerializer.Serialize(
+            new
+            {
+                oilLevel = oilLevel,
+                confidence = confidence,
+                warning = warning,
+            }
+        );
+        await _context.SaveChangesAsync(TestContext.Current.CancellationToken);
+
+        using var scope = _factory.Services.CreateScope();
+        var handler = ResolveHandler(scope);
+
+        await handler.OnWorkflowCompleted(workflow);
+
+        var published = Assert.Single(_factory.MqttPublisher.AnalysisResultMessages);
+        Assert.Equal(oilLevel.ToString("F2"), published.Value);
+        Assert.Equal(confidence * 100, published.Confidence);
+        Assert.Equal(warning, published.Warning);
+    }
 }

api/Services/ResultHandlers/WorkflowResultHandlers/CLOEResultHandler.cs

@@ -7,8 +7,8 @@ namespace api.Services.ResultHandlers.WorkflowResultHandlers;
 
 internal sealed class CLOEResult
 {
-    public float OilLevel { get; set; }
-    public float Confidence { get; set; }
+    public float? OilLevel { get; set; }
+    public float? Confidence { get; set; }
     public string? Warning { get; set; }
 }
 
@@ -58,9 +58,9 @@ public async Task OnWorkflowCompleted(Workflow workflow)
             AnalysisRunId = workflow.AnalysisRunId,
             AnalysisId = workflow.AnalysisRun.AnalysisId,
             AnalysisType = workflow.WorkflowType,
-            Value = result?.OilLevel.ToString("F2"),
+            Value = result?.OilLevel?.ToString("F2"),
             Unit = "fraction [oilLevel]",
-            Confidence = result is null ? null : result.Confidence * 100,
+            Confidence = result?.Confidence is { } c ? c * 100 : null,
             Warning = result?.Warning,
         };