[1028] Improve SuccessionAsUsage with implicit source

Bug: #1028
Signed-off-by: Arthur Daussy <arthur.daussy@obeo.fr>

Author: adaussy

CHANGELOG.adoc

@@ -18,6 +18,7 @@
 - https://github.com/eclipse-syson/syson/issues/1007[#1007] Improve direct edit on Feature elements to be able to set the `isDefault` and `isInitial` properties
 - https://github.com/eclipse-syson/syson/issues/1033[#1033] [explorer] Make it possible to create a diagram representation directly under a `root Namespace` element
 - https://github.com/eclipse-syson/syson/issues/960[#960] [general-view] In the selection dialog of the `subject` creation tool, display possible `Usage` candidates in a tree instead of a list.
+- https://github.com/eclipse-syson/syson/issues/1028[#1028] [import] Improve handling of `SuccessionAsUsage` with implicit source feature. 
 
 === New features
 
@@ -82,6 +83,7 @@ The changes are:
 - https://github.com/eclipse-syson/syson/issues/1018[#1018] [libraries] Make customizing the default metamodels and libraries available in SysML projects easier by making default implementation `SysONDefaultLibrariesConfiguration.java` more extensible.
 To do so, create a `@Primary @Configuration` component that extend `SysMLDefaultLibrariesConfiguration`, and optionally redefine `getDefaultLibraries()` method and/or `getDefaultEPackages()`.
 
+
 === New features
 
 - https://github.com/eclipse-syson/syson/issues/977[#977] [validation] SysON now implements the constraints (a.k.a. validation rules) from the SysMLv2 specification.

backend/application/syson-application/src/test/java/org/eclipse/syson/application/export/ImportExportTests.java

@@ -55,6 +55,64 @@ public void setUp() {
         this.checker = new SysmlImportExportChecker(this.sysmlLoader, this.editingDomainFactory, this.exporter, this.sysMLEditingContextProcessor);
     }
 
+    @Test
+    @DisplayName("Given a SuccessionAsUsage with an implicit source feature, when importing and exporting the model, then the exported text file should be the same as the imported one.")
+    public void checkSuccessionAsUsageImplicitSourceTest() throws IOException {
+        var input = """
+                action def ActionDef1 {
+                    action a0;
+                    action a1;
+                    action a2;
+                    then a1;
+                    then a0;
+                }""";
+
+        this.checker.check(input, input);
+    }
+
+    @Test
+    @DisplayName("Given a SuccessionAsUsage with an implicit source feature targeting the 'start' standard library element, when importing and exporting the model, then the exported text file should be semantically equal.")
+    public void checkSuccessionAsUsageImplicitSourceToStartTest() throws IOException {
+        var input = """
+                action def ActionDef1 {
+                    action a2;
+                    first start;
+                    then a2;
+                }""";
+        /**
+         * Here we have differences here because :
+         *
+         * <ul>
+         * <li>The strange construction of the Membership referencing 'start' is hard to detect so we chose to use the
+         * complete syntax "first source then target;"</li>
+         * <li>The current implementation of implicit specialization causes some issues during name de-resolution see
+         * https://github.com/eclipse-syson/syson/issues/1029</li>
+         * <ul>
+         */
+        var expected = """
+                action def ActionDef1 {
+                    action a2;
+                    first Actions::Action::start then a2;
+                }""";
+
+        this.checker.check(input, expected);
+    }
+
+    @Test
+    @DisplayName("Given a SuccessionAsUsage with an explicit source feature, when importing and exporting the model, then the exported text file should be the same as the imported one.")
+    public void checkSuccessionAsUsageExplicitSourceTest() throws IOException {
+        var input = """
+                action def ActionDef1 {
+                    action a0;
+                    action a1;
+                    action a2;
+                    first a0 then a1;
+                    first a1 then a2;
+                }""";
+
+        this.checker.check(input, input);
+    }
+
     /**
      * Test import/export on test file UseCaseTest.sysml. The content of UseCaseTest.sysml that have been copied below
      * is under LGPL-3.0-only license. The LGPL-3.0-only license is accessible at the root of this repository, in the
@@ -142,16 +200,15 @@ public void checkUseCaseTest() throws IOException {
                 }""";
 
         this.checker.check(input, expected);
-
     }
 
     /**
      * Test import/export simple PortDef and PortUsage.
      *
      * @throws IOException
      */
-    @DisplayName("Given a model with PortDefinition and PortUsage, when importing and exporting the model, then the exported text file should be the same as the imported one.")
     @Test
+    @DisplayName("Given a model with PortDefinition and PortUsage, when importing and exporting the model, then the exported text file should be the same as the imported one.")
     public void checkImportPort() throws IOException {
         var input = """
                 port def Port1;
@@ -166,8 +223,8 @@ public void checkImportPort() throws IOException {
      *
      * @throws IOException
      */
-    @DisplayName("Given a model with AttributeUsages with default and initial value, when importing and exporting the model, then the exported text file should be the same as the imported one.")
     @Test
+    @DisplayName("Given a model with AttributeUsages with default and initial value, when importing and exporting the model, then the exported text file should be the same as the imported one.")
     public void checkScalarValueAttribute() throws IOException {
         var input = """
                 package Occurrences {
@@ -238,7 +295,6 @@ public void checkImportTest() throws IOException {
                 }""";
 
         this.checker.check(input, expected);
-
     }
 
     /**
@@ -344,7 +400,5 @@ public void checkOccurrenceTest() throws IOException {
                 }""";
 
         this.checker.check(input, expected);
-
     }
-
 }