Unit test and document java_generic_symbol_type

Author: romainbrenguier

src/java_bytecode/java_types.h

@@ -579,6 +579,13 @@ class java_generic_symbol_typet : public symbol_typet
 public:
   typedef std::vector<reference_typet> generic_typest;
 
+  /// Construct a generic symbol type from base_ref and class_name_prefix which
+  /// must correspond to a generic type
+  /// (see \ref java_generic_symbol_typet::java_type_from_string).
+  /// For instance `java_generic_symbol_typet(symbol_typet("Map"),
+  /// "Ljava/util/Map<TK;TV;>;", "java/util/Map")` will generate a symbol type
+  /// with identifier "Map", and two generic types with identifier
+  /// "java/util/Map::K" and "java/util/Map::V" respectively.
   java_generic_symbol_typet(
     const symbol_typet &type,
     const std::string &base_ref,

unit/java_bytecode/java_types/java_generic_symbol_type.cpp

@@ -0,0 +1,31 @@
+/*******************************************************************\
+
+ Module: Unit tests for java_types
+
+ Author: Diffblue Ltd.
+
+\*******************************************************************/
+
+#include <testing-utils/catch.hpp>
+#include <java_types.h>
+
+SCENARIO("java_generic_symbol_type", "[core][java_types]")
+{
+  WHEN("MyType is LGenericClass<TX;TY;>;")
+  {
+    auto symbol_type = symbol_typet("MyType");
+    const auto generic_symbol_type = java_generic_symbol_typet(
+      symbol_type, "LGenericClass<TX;TY;>;", "PrefixClassName");
+
+    REQUIRE(generic_symbol_type.get_identifier() == "MyType");
+
+    auto types = generic_symbol_type.generic_types();
+    REQUIRE(types.size() == 2);
+
+    auto generic_var0 = to_java_generic_parameter(types[0]).type_variable();
+    REQUIRE(generic_var0.get_identifier() == "PrefixClassName::X");
+
+    auto generic_var1 = to_java_generic_parameter(types[1]).type_variable();
+    REQUIRE(generic_var1.get_identifier() == "PrefixClassName::Y");
+  }
+}