Add tests for `import module` instruction

tests/CMakeLists.txt

@@ -9,6 +9,7 @@ add_executable (unit_tests
   test_ArrayUtils.cpp
   test_ASTBuilder.cpp
   test_ASTDotPrinter.cpp
+  test_ASTModulesImporter.cpp
   test_ASTNode.cpp
   test_ASTNodeAffectationExpressionBuilder.cpp
   test_ASTNodeBinaryOperatorExpressionBuilder.cpp

tests/test_ASTModulesImporter.cpp

+#include <catch2/catch.hpp>
+
+#include <ASTBuilder.hpp>
+#include <ASTModulesImporter.hpp>
+#include <ASTNodeExpressionBuilder.hpp>
+#include <ASTNodeTypeCleaner.hpp>
+
+#include <SymbolTable.hpp>
+
+#include <PEGGrammar.hpp>
+
+#include <ASTPrinter.hpp>
+
+#define CHECK_AST(data, expected_output)                                                            \
+  {                                                                                                 \
+    static_assert(std::is_same_v<std::decay_t<decltype(data)>, std::string_view>);                  \
+    static_assert(std::is_same_v<std::decay_t<decltype(expected_output)>, std::string_view>);       \
+                                                                                                    \
+    string_input input{data, "test.pgs"};                                                           \
+    auto ast = ASTBuilder::build(input);                                                            \
+                                                                                                    \
+    ASTModulesImporter{*ast};                                                                       \
+    ASTNodeTypeCleaner<language::import_instruction>{*ast};                                         \
+                                                                                                    \
+    ASTNodeExpressionBuilder{*ast};                                                                 \
+    ExecUntilBreakOrContinue exec_policy;                                                           \
+    ast->execute(exec_policy);                                                                      \
+                                                                                                    \
+    std::stringstream ast_output;                                                                   \
+    ast_output << '\n' << ASTPrinter{*ast, ASTPrinter::Format::raw, {ASTPrinter::Info::data_type}}; \
+                                                                                                    \
+    REQUIRE(ast_output.str() == expected_output);                                                   \
+  }
+
+TEST_CASE("ASTModulesImporter", "[language]")
+{
+  SECTION("no module")
+  {
+    std::string_view data = R"(
+)";
+
+    std::string_view result = R"(
+(root:undefined)
+)";
+
+    CHECK_AST(data, result);
+  }
+
+  SECTION("module instruction removal")
+  {
+    std::string_view data = R"(
+import math;
+)";
+
+    std::string_view result = R"(
+(root:undefined)
+)";
+
+    CHECK_AST(data, result);
+  }
+
+  SECTION("error")
+  {
+    SECTION("unknown module")
+    {
+      std::string_view data = R"(
+import unknown_module;
+)";
+
+      string_input input{data, "test.pgs"};
+      auto ast = ASTBuilder::build(input);
+
+      REQUIRE_THROWS_AS(ASTModulesImporter{*ast}, parse_error);
+    }
+
+    SECTION("symbol already defined")
+    {
+      std::string_view data = R"(
+import math;
+)";
+
+      string_input input{data, "test.pgs"};
+      auto ast = ASTBuilder::build(input);
+
+      ast->m_symbol_table->add("sin", ast->begin());
+
+      REQUIRE_THROWS_AS(ASTModulesImporter{*ast}, parse_error);
+    }
+  }
+}