Fix build parameters wrong condition

src/main/java/org/gridsuite/loadflow/server/service/LoadFlowRunContext.java

@@ -28,7 +28,7 @@ public class LoadFlowRunContext extends AbstractComputationRunContext<LoadFlowPa
     private final UUID parametersUuid;
 
     public LoadFlowParameters buildParameters() {
-        LoadFlowParameters params = getParameters() == null || getParameters().getSpecificParameters() == null ?
+        LoadFlowParameters params = getParameters() == null || getParameters().getCommonParameters() == null ?
                 LoadFlowParameters.load() : getParameters().getCommonParameters();
         if (getParameters() == null || getParameters().getSpecificParameters() == null || getParameters().getSpecificParameters().isEmpty()) {
             return params; // no specific LF params

src/test/java/org/gridsuite/loadflow/server/LoadFlowRunContextTest.java

@@ -0,0 +1,125 @@
+/**
+ * Copyright (c) 2024, RTE (http://www.rte-france.com)
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+package org.gridsuite.loadflow.server;
+
+import com.powsybl.commons.PowsyblException;
+import com.powsybl.commons.config.PlatformConfig;
+import com.powsybl.commons.extensions.Extension;
+import com.powsybl.loadflow.LoadFlowParameters;
+import com.powsybl.loadflow.LoadFlowProvider;
+import org.gridsuite.loadflow.server.dto.parameters.LoadFlowParametersValues;
+import org.gridsuite.loadflow.server.service.LoadFlowRunContext;
+import org.junit.jupiter.api.Test;
+import org.mockito.MockedStatic;
+import org.mockito.Mockito;
+import java.util.Collections;
+import java.util.Map;
+import java.util.Optional;
+import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.Mockito.*;
+
+class LoadFlowRunContextTest {
+
+    @Test
+    void testBuildParametersWithNullParameters() {
+        LoadFlowRunContext context = LoadFlowRunContext.builder()
+                .parameters(null)
+                .build();
+
+        LoadFlowParameters params = context.buildParameters();
+        assertNotNull(params);
+    }
+
+    @Test
+    void testBuildParametersWithCommonParameters() {
+        LoadFlowParameters commonParams = LoadFlowParameters.load();
+        LoadFlowParametersValues parametersValues = LoadFlowParametersValues.builder()
+                .commonParameters(commonParams)
+                .build();
+
+        LoadFlowRunContext context = LoadFlowRunContext.builder()
+                .parameters(parametersValues)
+                .build();
+
+        LoadFlowParameters params = context.buildParameters();
+        assertEquals(commonParams, params);
+    }
+
+    @Test
+    void testBuildParametersWithSpecificParameters() {
+        LoadFlowParameters commonParams = LoadFlowParameters.load();
+        Map<String, String> specificParams = Map.of("key", "value");
+        LoadFlowParametersValues parametersValues = LoadFlowParametersValues.builder()
+                .commonParameters(commonParams)
+                .specificParameters(specificParams)
+                .build();
+
+        LoadFlowProvider provider = mock(LoadFlowProvider.class);
+        Extension<LoadFlowParameters> extension = mock(Extension.class);
+
+        try (MockedStatic<LoadFlowProvider> mockedProvider = Mockito.mockStatic(LoadFlowProvider.class)) {
+            mockedProvider.when(LoadFlowProvider::findAll).thenReturn(Collections.singletonList(provider));
+            when(provider.getName()).thenReturn("provider");
+            when(provider.loadSpecificParameters(any(PlatformConfig.class))).thenReturn(Optional.of(extension));
+
+            LoadFlowRunContext context = LoadFlowRunContext.builder()
+                    .provider("provider")
+                    .parameters(parametersValues)
+                    .build();
+
+            LoadFlowParameters params = context.buildParameters();
+            assertNotNull(params);
+            verify(provider).updateSpecificParameters(extension, specificParams);
+        }
+    }
+
+    @Test
+    void testBuildParametersWithProviderNotFound() {
+        LoadFlowParameters commonParams = LoadFlowParameters.load();
+        Map<String, String> specificParams = Map.of("key", "value");
+        LoadFlowParametersValues parametersValues = LoadFlowParametersValues.builder()
+                .commonParameters(commonParams)
+                .specificParameters(specificParams)
+                .build();
+
+        try (MockedStatic<LoadFlowProvider> mockedProvider = Mockito.mockStatic(LoadFlowProvider.class)) {
+            mockedProvider.when(LoadFlowProvider::findAll).thenReturn(Collections.emptyList());
+
+            LoadFlowRunContext context = LoadFlowRunContext.builder()
+                    .provider("provider")
+                    .parameters(parametersValues)
+                    .build();
+
+            assertThrows(PowsyblException.class, context::buildParameters);
+        }
+    }
+
+    @Test
+    void testBuildParametersWithExtensionNotFound() {
+        LoadFlowParameters commonParams = LoadFlowParameters.load();
+        Map<String, String> specificParams = Map.of("key", "value");
+        LoadFlowParametersValues parametersValues = LoadFlowParametersValues.builder()
+                .commonParameters(commonParams)
+                .specificParameters(specificParams)
+                .build();
+
+        LoadFlowProvider provider = mock(LoadFlowProvider.class);
+
+        try (MockedStatic<LoadFlowProvider> mockedProvider = Mockito.mockStatic(LoadFlowProvider.class)) {
+            mockedProvider.when(LoadFlowProvider::findAll).thenReturn(Collections.singletonList(provider));
+            when(provider.getName()).thenReturn("provider");
+            when(provider.loadSpecificParameters(any(PlatformConfig.class))).thenReturn(Optional.empty());
+
+            LoadFlowRunContext context = LoadFlowRunContext.builder()
+                    .provider("provider")
+                    .parameters(parametersValues)
+                    .build();
+
+            assertThrows(PowsyblException.class, context::buildParameters);
+        }
+    }
+}