Document BasicStringWriter

test/string-test.cc

@@ -10,6 +10,63 @@
 #include "fmt/string.h"
 #include "gtest/gtest.h"
 
+using fmt::internal::StringBuffer;
+
+TEST(StringBufferTest, Empty) {
+  StringBuffer<char> buffer;
+  EXPECT_EQ(0, buffer.size());
+  EXPECT_EQ(0, buffer.capacity());
+  std::string data;
+  // std::string may have initial capacity.
+  std::size_t capacity = data.capacity();
+  buffer.move_to(data);
+  EXPECT_EQ("", data);
+  EXPECT_EQ(capacity, data.capacity());
+}
+
+TEST(StringBufferTest, Reserve) {
+  StringBuffer<char> buffer;
+  std::size_t capacity = std::string().capacity() + 10;
+  buffer.reserve(capacity);
+  EXPECT_EQ(0, buffer.size());
+  EXPECT_EQ(capacity, buffer.capacity());
+  std::string data;
+  buffer.move_to(data);
+  EXPECT_EQ("", data);
+}
+
+TEST(StringBufferTest, Resize) {
+  StringBuffer<char> buffer;
+  std::size_t size = std::string().capacity() + 10;
+  buffer.resize(size);
+  EXPECT_EQ(size, buffer.size());
+  EXPECT_EQ(size, buffer.capacity());
+  std::string data;
+  buffer.move_to(data);
+  EXPECT_EQ(size, data.size());
+}
+
+TEST(StringBufferTest, MoveTo) {
+  StringBuffer<char> buffer;
+  std::size_t size = std::string().capacity() + 10;
+  buffer.resize(size);
+  const char *p = &buffer[0];
+  std::string data;
+  buffer.move_to(data);
+  EXPECT_EQ(p, &data[0]);
+  EXPECT_EQ(0, buffer.size());
+  EXPECT_EQ(0, buffer.capacity());
+}
+
+TEST(StringWriterTest, MoveTo) {
+  fmt::StringWriter out;
+  out << "The answer is " << 42 << "\n";
+  std::string s;
+  out.move_to(s);
+  EXPECT_EQ("The answer is 42\n", s);
+  EXPECT_EQ(0, out.size());
+}
+
 TEST(StringTest, ToString) {
   EXPECT_EQ("42", fmt::to_string(42));
 }