libnixt/serialize: add unit tests for ExprInt and ExprFloat

libnixt/meson.build

@@ -31,6 +31,7 @@ nixt = declare_dependency(include_directories: libnixdInc,
 )
 
 libnixt_test_exe = executable('test-libnixt',
+                              'test/Serialize.cpp',
                               'test/SerializeSupport.cpp',
                               dependencies: [ gtest_main, nixt ])
 

libnixt/test/Serialize.cpp

@@ -0,0 +1,63 @@
+#include <gtest/gtest.h>
+
+#include "nixt/Serialize.h"
+
+#include <nix/nixexpr.hh>
+
+#include <bit>
+
+using namespace nixt::serialize;
+
+static_assert(std::endian::native == std::endian::little);
+
+namespace {
+
+class SerializeTest : public testing::Test {
+protected:
+  nix::PosTable PT;
+  nix::SymbolTable ST;
+  std::ostringstream OS;
+  std::string write(const nix::Expr *E) {
+    nixt::serialize::write(OS, ST, PT, E);
+    return OS.str();
+  }
+};
+
+void checkASTHeader(const ASTHeader &H) {
+  EXPECT_EQ(std::memcmp(H.Magic, "\x7FNixAST\0", 8), 0);
+  EXPECT_EQ(H.Version, 1);
+}
+
+void checkASTHeader(const char *Raw) {
+  ASTHeader Header;
+  std::memcpy(&Header, Raw, sizeof(ASTHeader));
+  checkASTHeader(Header);
+}
+
+} // namespace
+
+TEST_F(SerializeTest, ExprInt) {
+  nix::ExprInt E(0x2adeadbeef);
+  std::string Result = write(&E);
+  const char Expected[] = "\x6\0\0\0\xEF\xBE\xAD\xDE\x2A\0\0";
+  checkASTHeader(Result.c_str());
+  auto Content = std::string_view(Result).substr(sizeof(ASTHeader));
+  EXPECT_TRUE(std::memcmp(Expected, Content.begin(), sizeof(Expected)) == 0);
+  EXPECT_EQ(Content.size(), sizeof(Expected));
+}
+
+TEST_F(SerializeTest, ExprFloat) {
+  union {
+    double D;
+    std::uint64_t U;
+  } Data;
+  Data.U = 0x2adeadbeef;
+
+  nix::ExprFloat E(Data.D);
+  std::string Result = write(&E);
+  const char Expected[] = "\x4\0\0\0\xEF\xBE\xAD\xDE\x2A\0\0";
+  checkASTHeader(Result.c_str());
+  auto Content = std::string_view(Result).substr(sizeof(ASTHeader));
+  EXPECT_TRUE(std::memcmp(Expected, Content.begin(), sizeof(Expected)) == 0);
+  EXPECT_EQ(Content.size(), sizeof(Expected));
+}