Unit test java_type_from_string and fix doc

Unit-testing this function revealed some mistakes in the examples given
in the documentation.

Author: romainbrenguier

src/java_bytecode/java_types.cpp

@@ -416,8 +416,10 @@ size_t find_closing_semi_colon_for_reference_type(
 /// representation thereof.
 ///
 /// Example use are object types like "Ljava/lang/Integer;", type
-/// variables/parameters like "TE;" which require a non-empty \p class_name
-/// or generic types like "Ljava/util/List<T>;" or "Ljava/util/List<Integer>;"
+/// variables/parameters like "TE;" which require a non-empty
+/// \p class_name_prefix or generic types like "Ljava/util/List<TE;>;"
+/// or "Ljava/util/List<Ljava/lang/Integer;>;" also requiring
+/// \p class_name_prefix.
 ///
 /// \param src: the string representation as used in the class file
 /// \param class_name_prefix: name of class to append to generic type

unit/java_bytecode/java_types/java_type_from_string.cpp

@@ -0,0 +1,48 @@
+/*******************************************************************\
+
+ Module: Unit tests for java_types
+
+ Author: Diffblue Ltd.
+
+\*******************************************************************/
+
+#include <testing-utils/catch.hpp>
+#include <java_bytecode/java_types.h>
+
+SCENARIO("java_type_from_string", "[core][java_types]")
+{
+  // TODO : add more cases, the current test is not comprehensive
+
+  GIVEN("Ljava/lang/Integer;")
+  {
+    const auto integer_type = java_type_from_string("Ljava/lang/Integer;", "");
+    REQUIRE(integer_type != nil_typet());
+  }
+
+  GIVEN("TE;")
+  {
+    const auto generic_type_E = java_type_from_string("TE;", "MyClass");
+    REQUIRE(generic_type_E != nil_typet());
+  }
+
+  GIVEN("Ljava/util/List<TX;>;")
+  {
+    const auto generic_list_type =
+      java_type_from_string("Ljava/util/List<TX;>;", "java.util.List");
+    REQUIRE(generic_list_type != nil_typet());
+  }
+
+  GIVEN("Ljava/util/List<Ljava/lang/Integer>;")
+  {
+    const auto integer_list_type =
+      java_type_from_string("Ljava/util/List<Ljava/lang/Integer;>;", "");
+    REQUIRE(integer_list_type != nil_typet());
+  }
+
+  GIVEN("Ljava/util/Map<TK;TV;>;")
+  {
+    const auto generic_symbol_type =
+      java_type_from_string("Ljava/util/Map<TK;TV;>;", "java.util.Map");
+    REQUIRE(generic_symbol_type != nil_typet());
+  }
+}