parse_csv_test.cc

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/*
                          Aleph_w
 
  Data structures & Algorithms
  version 2.0.0b
  https://github.com/lrleon/Aleph-w
 
  This file is part of Aleph-w library
 
  Copyright (c) 2002-2026 Leandro Rabindranath Leon
 
  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:
 
  The above copyright notice and this permission notice shall be included in all
  copies or substantial portions of the Software.
 
  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  SOFTWARE.
*/
 
 
#include <gtest/gtest.h>
#include <sstream>
#include <fstream>
#include <cstdio>
#include <parse-csv.H>
 
using namespace Aleph;
 
//============================================================================
// csv_read_row Tests - Stream Input
//============================================================================
 
class CsvReadRowStreamTest : public ::testing::Test {};
 
TEST_F(CsvReadRowStreamTest, SimpleRow)
{
  std::istringstream ss("a,b,c\n");
  Array<std::string> row = csv_read_row(ss);
  
  ASSERT_EQ(row.size(), 3u);
  EXPECT_EQ(row(0), "a");
  EXPECT_EQ(row(1), "b");
  EXPECT_EQ(row(2), "c");
}
 
TEST_F(CsvReadRowStreamTest, SingleField)
{
  std::istringstream ss("hello\n");
  Array<std::string> row = csv_read_row(ss);
  
  ASSERT_EQ(row.size(), 1u);
  EXPECT_EQ(row(0), "hello");
}
 
TEST_F(CsvReadRowStreamTest, EmptyFields)
{
  std::istringstream ss(",b,,d\n");
  Array<std::string> row = csv_read_row(ss);
  
  ASSERT_EQ(row.size(), 4u);
  EXPECT_EQ(row(0), "");
  EXPECT_EQ(row(1), "b");
  EXPECT_EQ(row(2), "");
  EXPECT_EQ(row(3), "d");
}
 
TEST_F(CsvReadRowStreamTest, QuotedField)
{
  std::istringstream ss("a,\"hello world\",c\n");
  Array<std::string> row = csv_read_row(ss);
  
  ASSERT_EQ(row.size(), 3u);
  EXPECT_EQ(row(0), "a");
  EXPECT_EQ(row(1), "hello world");
  EXPECT_EQ(row(2), "c");
}
 
TEST_F(CsvReadRowStreamTest, QuotedFieldWithDelimiter)
{
  std::istringstream ss("a,\"hello, world\",c\n");
  Array<std::string> row = csv_read_row(ss);
  
  ASSERT_EQ(row.size(), 3u);
  EXPECT_EQ(row(0), "a");
  EXPECT_EQ(row(1), "hello, world");
  EXPECT_EQ(row(2), "c");
}
 
TEST_F(CsvReadRowStreamTest, EscapedQuotes)
{
  std::istringstream ss("a,\"say \"\"hi\"\"\",c\n");
  Array<std::string> row = csv_read_row(ss);
  
  ASSERT_EQ(row.size(), 3u);
  EXPECT_EQ(row(0), "a");
  EXPECT_EQ(row(1), "say \"hi\"");
  EXPECT_EQ(row(2), "c");
}
 
TEST_F(CsvReadRowStreamTest, QuotedFieldWithNewline)
{
  std::istringstream ss("a,\"line1\nline2\",c\n");
  Array<std::string> row = csv_read_row(ss);
  
  ASSERT_EQ(row.size(), 3u);
  EXPECT_EQ(row(0), "a");
  EXPECT_EQ(row(1), "line1\nline2");
  EXPECT_EQ(row(2), "c");
}
 
TEST_F(CsvReadRowStreamTest, CRLFLineEnding)
{
  std::istringstream ss("a,b,c\r\n");
  Array<std::string> row = csv_read_row(ss);
  
  ASSERT_EQ(row.size(), 3u);
  EXPECT_EQ(row(0), "a");
  EXPECT_EQ(row(1), "b");
  EXPECT_EQ(row(2), "c");
}
 
TEST_F(CsvReadRowStreamTest, NoTrailingNewline)
{
  std::istringstream ss("a,b,c");
  Array<std::string> row = csv_read_row(ss);
  
  ASSERT_EQ(row.size(), 3u);
  EXPECT_EQ(row(0), "a");
  EXPECT_EQ(row(1), "b");
  EXPECT_EQ(row(2), "c");
}
 
TEST_F(CsvReadRowStreamTest, CustomDelimiter)
{
  std::istringstream ss("a;b;c\n");
  Array<std::string> row = csv_read_row(ss, ';');
  
  ASSERT_EQ(row.size(), 3u);
  EXPECT_EQ(row(0), "a");
  EXPECT_EQ(row(1), "b");
  EXPECT_EQ(row(2), "c");
}
 
TEST_F(CsvReadRowStreamTest, TabDelimiter)
{
  std::istringstream ss("a\tb\tc\n");
  Array<std::string> row = csv_read_row(ss, '\t');
  
  ASSERT_EQ(row.size(), 3u);
  EXPECT_EQ(row(0), "a");
  EXPECT_EQ(row(1), "b");
  EXPECT_EQ(row(2), "c");
}
 
TEST_F(CsvReadRowStreamTest, MultipleRows)
{
  std::istringstream ss("a,b,c\n1,2,3\nx,y,z\n");
  
  Array<std::string> row1 = csv_read_row(ss);
  Array<std::string> row2 = csv_read_row(ss);
  Array<std::string> row3 = csv_read_row(ss);
  
  ASSERT_EQ(row1.size(), 3u);
  EXPECT_EQ(row1(0), "a");
  
  ASSERT_EQ(row2.size(), 3u);
  EXPECT_EQ(row2(0), "1");
  
  ASSERT_EQ(row3.size(), 3u);
  EXPECT_EQ(row3(0), "x");
}
 
TEST_F(CsvReadRowStreamTest, EmptyStream)
{
  std::istringstream ss("");
  Array<std::string> row = csv_read_row(ss);
  
  // Empty stream produces one empty field (consistent with CSV parsers)
  // An empty string "" still has one field (empty)
  EXPECT_LE(row.size(), 1u);
}
 
TEST_F(CsvReadRowStreamTest, WhitespacePreserved)
{
  std::istringstream ss("  a  ,  b  ,  c  \n");
  Array<std::string> row = csv_read_row(ss);
  
  ASSERT_EQ(row.size(), 3u);
  EXPECT_EQ(row(0), "  a  ");
  EXPECT_EQ(row(1), "  b  ");
  EXPECT_EQ(row(2), "  c  ");
}
 
//============================================================================
// csv_read_row Tests - String Input
//============================================================================
 
class CsvReadRowStringTest : public ::testing::Test {};
 
TEST_F(CsvReadRowStringTest, SimpleRow)
{
  std::string line = "a,b,c";
  Array<std::string> row = csv_read_row(line);
  
  ASSERT_EQ(row.size(), 3u);
  EXPECT_EQ(row(0), "a");
  EXPECT_EQ(row(1), "b");
  EXPECT_EQ(row(2), "c");
}
 
TEST_F(CsvReadRowStringTest, QuotedFieldInString)
{
  std::string line = "a,\"hello, world\",c";
  Array<std::string> row = csv_read_row(line);
  
  ASSERT_EQ(row.size(), 3u);
  EXPECT_EQ(row(1), "hello, world");
}
 
TEST_F(CsvReadRowStringTest, EscapedQuotesInString)
{
  std::string line = "a,\"say \"\"hello\"\"\",c";
  Array<std::string> row = csv_read_row(line);
  
  ASSERT_EQ(row.size(), 3u);
  EXPECT_EQ(row(1), "say \"hello\"");
}
 
//============================================================================
// csv_read_all Tests
//============================================================================
 
class CsvReadAllTest : public ::testing::Test {};
 
TEST_F(CsvReadAllTest, MultipleRows)
{
  std::istringstream ss("a,b,c\n1,2,3\nx,y,z\n");
  Array<Array<std::string>> data = csv_read_all(ss);
  
  ASSERT_EQ(data.size(), 3u);
  EXPECT_EQ(data(0)(0), "a");
  EXPECT_EQ(data(1)(0), "1");
  EXPECT_EQ(data(2)(0), "x");
}
 
TEST_F(CsvReadAllTest, SingleRow)
{
  std::istringstream ss("a,b,c\n");
  Array<Array<std::string>> data = csv_read_all(ss);
  
  ASSERT_EQ(data.size(), 1u);
  EXPECT_EQ(data(0).size(), 3u);
}
 
TEST_F(CsvReadAllTest, NoTrailingNewline)
{
  std::istringstream ss("a,b,c\n1,2,3");
  Array<Array<std::string>> data = csv_read_all(ss);
  
  ASSERT_EQ(data.size(), 2u);
  EXPECT_EQ(data(1)(2), "3");
}
 
TEST_F(CsvReadAllTest, EmptyStream)
{
  std::istringstream ss("");
  Array<Array<std::string>> data = csv_read_all(ss);
  
  // Empty stream may produce 0 or 1 empty rows depending on implementation
  EXPECT_LE(data.size(), 1u);
}
 
TEST_F(CsvReadAllTest, RowsWithDifferentLengths)
{
  std::istringstream ss("a,b,c\n1,2\nx,y,z,w\n");
  Array<Array<std::string>> data = csv_read_all(ss);
  
  ASSERT_EQ(data.size(), 3u);
  EXPECT_EQ(data(0).size(), 3u);
  EXPECT_EQ(data(1).size(), 2u);
  EXPECT_EQ(data(2).size(), 4u);
}
 
TEST_F(CsvReadAllTest, CustomDelimiter)
{
  std::istringstream ss("a;b;c\n1;2;3\n");
  Array<Array<std::string>> data = csv_read_all(ss, ';');
  
  ASSERT_EQ(data.size(), 2u);
  EXPECT_EQ(data(0)(1), "b");
  EXPECT_EQ(data(1)(1), "2");
}
 
//============================================================================
// csv_escape Tests
//============================================================================
 
class CsvEscapeTest : public ::testing::Test {};
 
TEST_F(CsvEscapeTest, NoEscapingNeeded)
{
  EXPECT_EQ(csv_escape("hello"), "hello");
  EXPECT_EQ(csv_escape("world123"), "world123");
  EXPECT_EQ(csv_escape(""), "");
}
 
TEST_F(CsvEscapeTest, EscapeDelimiter)
{
  EXPECT_EQ(csv_escape("hello, world"), "\"hello, world\"");
}
 
TEST_F(CsvEscapeTest, EscapeQuotes)
{
  EXPECT_EQ(csv_escape("say \"hi\""), "\"say \"\"hi\"\"\"");
}
 
TEST_F(CsvEscapeTest, EscapeNewline)
{
  EXPECT_EQ(csv_escape("line1\nline2"), "\"line1\nline2\"");
}
 
TEST_F(CsvEscapeTest, EscapeCarriageReturn)
{
  EXPECT_EQ(csv_escape("line1\rline2"), "\"line1\rline2\"");
}
 
TEST_F(CsvEscapeTest, EscapeMultipleSpecialChars)
{
  EXPECT_EQ(csv_escape("a,\"b\"\nc"), "\"a,\"\"b\"\"\nc\"");
}
 
TEST_F(CsvEscapeTest, CustomDelimiter)
{
  EXPECT_EQ(csv_escape("a;b", ';'), "\"a;b\"");
  EXPECT_EQ(csv_escape("a,b", ';'), "a,b");  // Comma not special with semicolon delimiter
}
 
//============================================================================
// csv_write_row Tests
//============================================================================
 
class CsvWriteRowTest : public ::testing::Test {};
 
TEST_F(CsvWriteRowTest, SimpleRow)
{
  Array<std::string> row;
  row.append("a");
  row.append("b");
  row.append("c");
  
  std::ostringstream out;
  csv_write_row(out, row);
  
  EXPECT_EQ(out.str(), "a,b,c\n");
}
 
TEST_F(CsvWriteRowTest, RowWithQuotedFields)
{
  Array<std::string> row;
  row.append("name");
  row.append("hello, world");  // Contains comma
  row.append("value");
  
  std::ostringstream out;
  csv_write_row(out, row);
  
  EXPECT_EQ(out.str(), "name,\"hello, world\",value\n");
}
 
TEST_F(CsvWriteRowTest, RowWithQuotesInField)
{
  Array<std::string> row;
  row.append("say \"hi\"");
  
  std::ostringstream out;
  csv_write_row(out, row);
  
  EXPECT_EQ(out.str(), "\"say \"\"hi\"\"\"\n");
}
 
TEST_F(CsvWriteRowTest, EmptyRow)
{
  Array<std::string> row;
  
  std::ostringstream out;
  csv_write_row(out, row);
  
  EXPECT_EQ(out.str(), "\n");
}
 
TEST_F(CsvWriteRowTest, SingleField)
{
  Array<std::string> row;
  row.append("single");
  
  std::ostringstream out;
  csv_write_row(out, row);
  
  EXPECT_EQ(out.str(), "single\n");
}
 
TEST_F(CsvWriteRowTest, CustomDelimiter)
{
  Array<std::string> row;
  row.append("a");
  row.append("b");
  row.append("c");
  
  std::ostringstream out;
  csv_write_row(out, row, ';');
  
  EXPECT_EQ(out.str(), "a;b;c\n");
}
 
TEST_F(CsvWriteRowTest, CustomLineEnding)
{
  Array<std::string> row;
  row.append("a");
  row.append("b");
  
  std::ostringstream out;
  csv_write_row(out, row, ',', "\r\n");
  
  EXPECT_EQ(out.str(), "a,b\r\n");
}
 
//============================================================================
// csv_write_all Tests
//============================================================================
 
class CsvWriteAllTest : public ::testing::Test {};
 
TEST_F(CsvWriteAllTest, MultipleRows)
{
  Array<Array<std::string>> data;
  
  Array<std::string> row1;
  row1.append("a");
  row1.append("b");
  data.append(row1);
  
  Array<std::string> row2;
  row2.append("1");
  row2.append("2");
  data.append(row2);
  
  std::ostringstream out;
  csv_write_all(out, data);
  
  EXPECT_EQ(out.str(), "a,b\n1,2\n");
}
 
TEST_F(CsvWriteAllTest, EmptyData)
{
  Array<Array<std::string>> data;
  
  std::ostringstream out;
  csv_write_all(out, data);
  
  EXPECT_EQ(out.str(), "");
}
 
//============================================================================
// csv_read_file / csv_write_file Tests
//============================================================================
 
class CsvFileTest : public ::testing::Test
{
protected:
  void SetUp() override
  {
    test_filename = "/tmp/aleph_csv_test_" + std::to_string(rand()) + ".csv";
  }
  
  void TearDown() override
  {
    std::remove(test_filename.c_str());
  }
  
  std::string test_filename;
};
 
TEST_F(CsvFileTest, WriteAndReadFile)
{
  // Create test data
  Array<Array<std::string>> data;
  
  Array<std::string> header;
  header.append("name");
  header.append("value");
  data.append(header);
  
  Array<std::string> row1;
  row1.append("item1");
  row1.append("100");
  data.append(row1);
  
  Array<std::string> row2;
  row2.append("item2");
  row2.append("200");
  data.append(row2);
  
  // Write to file
  ASSERT_NO_THROW(csv_write_file(test_filename, data));
  
  // Read back
  Array<Array<std::string>> read_data;
  ASSERT_NO_THROW(read_data = csv_read_file(test_filename));
  
  // Verify
  ASSERT_EQ(read_data.size(), 3u);
  EXPECT_EQ(read_data(0)(0), "name");
  EXPECT_EQ(read_data(0)(1), "value");
  EXPECT_EQ(read_data(1)(0), "item1");
  EXPECT_EQ(read_data(1)(1), "100");
  EXPECT_EQ(read_data(2)(0), "item2");
  EXPECT_EQ(read_data(2)(1), "200");
}
 
TEST_F(CsvFileTest, ReadNonExistentFile)
{
  EXPECT_THROW(csv_read_file("/nonexistent/path/file.csv"), std::runtime_error);
}
 
TEST_F(CsvFileTest, WriteToInvalidPath)
{
  Array<Array<std::string>> data;
  Array<std::string> row;
  row.append("test");
  data.append(row);
  
  EXPECT_THROW(csv_write_file("/nonexistent/path/file.csv", data), std::runtime_error);
}
 
TEST_F(CsvFileTest, WriteAndReadWithSpecialCharacters)
{
  Array<Array<std::string>> data;
  
  Array<std::string> row;
  row.append("field with, comma");
  row.append("field with \"quotes\"");
  row.append("field with\nnewline");
  data.append(row);
  
  csv_write_file(test_filename, data);
  Array<Array<std::string>> read_data = csv_read_file(test_filename);
  
  ASSERT_EQ(read_data.size(), 1u);
  ASSERT_EQ(read_data(0).size(), 3u);
  EXPECT_EQ(read_data(0)(0), "field with, comma");
  EXPECT_EQ(read_data(0)(1), "field with \"quotes\"");
  EXPECT_EQ(read_data(0)(2), "field with\nnewline");
}
 
//============================================================================
// csv_num_columns Tests
//============================================================================
 
class CsvNumColumnsTest : public ::testing::Test {};
 
TEST_F(CsvNumColumnsTest, BasicUsage)
{
  std::string line = "a,b,c,d,e";
  Array<std::string> row = csv_read_row(line);
  
  EXPECT_EQ(csv_num_columns(row), 5u);
}
 
TEST_F(CsvNumColumnsTest, EmptyRow)
{
  Array<std::string> row;
  EXPECT_EQ(csv_num_columns(row), 0u);
}
 
TEST_F(CsvNumColumnsTest, SingleColumn)
{
  std::string line = "single";
  Array<std::string> row = csv_read_row(line);
  
  EXPECT_EQ(csv_num_columns(row), 1u);
}
 
//============================================================================
// csv_is_rectangular Tests
//============================================================================
 
class CsvIsRectangularTest : public ::testing::Test {};
 
TEST_F(CsvIsRectangularTest, EmptyData)
{
  Array<Array<std::string>> data;
  EXPECT_TRUE(csv_is_rectangular(data));
}
 
TEST_F(CsvIsRectangularTest, RectangularData)
{
  std::istringstream ss("a,b,c\n1,2,3\nx,y,z\n");
  Array<Array<std::string>> data = csv_read_all(ss);
  
  EXPECT_TRUE(csv_is_rectangular(data));
}
 
TEST_F(CsvIsRectangularTest, NonRectangularData)
{
  std::istringstream ss("a,b,c\n1,2\nx,y,z,w\n");
  Array<Array<std::string>> data = csv_read_all(ss);
  
  EXPECT_FALSE(csv_is_rectangular(data));
}
 
TEST_F(CsvIsRectangularTest, SingleRow)
{
  std::istringstream ss("a,b,c\n");
  Array<Array<std::string>> data = csv_read_all(ss);
  
  EXPECT_TRUE(csv_is_rectangular(data));
}
 
//============================================================================
// csv_get_column Tests
//============================================================================
 
class CsvGetColumnTest : public ::testing::Test {};
 
TEST_F(CsvGetColumnTest, BasicColumn)
{
  std::istringstream ss("name,age\nAlice,30\nBob,25\n");
  Array<Array<std::string>> data = csv_read_all(ss);
  
  Array<std::string> names = csv_get_column(data, 0);
  
  ASSERT_EQ(names.size(), 3u);
  EXPECT_EQ(names(0), "name");
  EXPECT_EQ(names(1), "Alice");
  EXPECT_EQ(names(2), "Bob");
}
 
TEST_F(CsvGetColumnTest, SecondColumn)
{
  std::istringstream ss("name,age\nAlice,30\nBob,25\n");
  Array<Array<std::string>> data = csv_read_all(ss);
  
  Array<std::string> ages = csv_get_column(data, 1);
  
  ASSERT_EQ(ages.size(), 3u);
  EXPECT_EQ(ages(0), "age");
  EXPECT_EQ(ages(1), "30");
  EXPECT_EQ(ages(2), "25");
}
 
TEST_F(CsvGetColumnTest, OutOfRangeColumn)
{
  std::istringstream ss("a,b\n1,2\n");
  Array<Array<std::string>> data = csv_read_all(ss);
  
  EXPECT_THROW(csv_get_column(data, 5), std::out_of_range);
}
 
TEST_F(CsvGetColumnTest, EmptyData)
{
  Array<Array<std::string>> data;
  Array<std::string> column = csv_get_column(data, 0);
  
  EXPECT_EQ(column.size(), 0u);
}
 
//============================================================================
// csv_to_number Tests
//============================================================================
 
class CsvToNumberTest : public ::testing::Test {};
 
TEST_F(CsvToNumberTest, ConvertToInt)
{
  EXPECT_EQ(csv_to_number<int>("42"), 42);
  EXPECT_EQ(csv_to_number<int>("-17"), -17);
  EXPECT_EQ(csv_to_number<int>("0"), 0);
}
 
TEST_F(CsvToNumberTest, ConvertToLong)
{
  EXPECT_EQ(csv_to_number<long>("1000000000"), 1000000000L);
  EXPECT_EQ(csv_to_number<long>("-999999999"), -999999999L);
}
 
TEST_F(CsvToNumberTest, ConvertToDouble)
{
  EXPECT_DOUBLE_EQ(csv_to_number<double>("3.14159"), 3.14159);
  EXPECT_DOUBLE_EQ(csv_to_number<double>("-2.5"), -2.5);
  EXPECT_DOUBLE_EQ(csv_to_number<double>("1e10"), 1e10);
}
 
TEST_F(CsvToNumberTest, ConvertToFloat)
{
  EXPECT_FLOAT_EQ(csv_to_number<float>("3.14f"), 3.14f);
  EXPECT_FLOAT_EQ(csv_to_number<float>("-1.5"), -1.5f);
}
 
TEST_F(CsvToNumberTest, InvalidIntConversion)
{
  EXPECT_THROW((void)csv_to_number<int>("not_a_number"), std::invalid_argument);
  EXPECT_THROW((void)csv_to_number<int>(""), std::invalid_argument);
}
 
TEST_F(CsvToNumberTest, InvalidDoubleConversion)
{
  EXPECT_THROW((void)csv_to_number<double>("abc"), std::invalid_argument);
}
 
TEST_F(CsvToNumberTest, ConvertWithWhitespace)
{
  // std::stoi handles leading whitespace
  EXPECT_EQ(csv_to_number<int>("  42"), 42);
}
 
//============================================================================
// Round-trip Tests
//============================================================================
 
class CsvRoundTripTest : public ::testing::Test {};
 
TEST_F(CsvRoundTripTest, SimpleDataRoundTrip)
{
  // Original data
  std::istringstream input("name,value\ntest,100\n");
  Array<Array<std::string>> original = csv_read_all(input);
  
  // Write to string
  std::ostringstream output;
  csv_write_all(output, original);
  
  // Parse back
  std::istringstream input2(output.str());
  Array<Array<std::string>> parsed = csv_read_all(input2);
  
  // Compare
  ASSERT_EQ(parsed.size(), original.size());
  for (size_t i = 0; i < original.size(); ++i)
  {
    ASSERT_EQ(parsed(i).size(), original(i).size());
    for (size_t j = 0; j < original(i).size(); ++j)
      EXPECT_EQ(parsed(i)(j), original(i)(j));
  }
}
 
TEST_F(CsvRoundTripTest, ComplexDataRoundTrip)
{
  // Create data with special characters
  Array<Array<std::string>> original;
  
  Array<std::string> row1;
  row1.append("simple");
  row1.append("with, comma");
  row1.append("with \"quotes\"");
  row1.append("with\nnewline");
  original.append(row1);
  
  Array<std::string> row2;
  row2.append("\"\"\"");  // Just quotes
  row2.append(",,,");    // Just commas
  row2.append("\n\r\n"); // Newlines
  row2.append("");       // Empty
  original.append(row2);
  
  // Round trip
  std::ostringstream output;
  csv_write_all(output, original);
  
  std::istringstream input(output.str());
  Array<Array<std::string>> parsed = csv_read_all(input);
  
  // Verify
  ASSERT_EQ(parsed.size(), original.size());
  for (size_t i = 0; i < original.size(); ++i)
  {
    ASSERT_EQ(parsed(i).size(), original(i).size()) 
      << "Row " << i << " size mismatch";
    for (size_t j = 0; j < original(i).size(); ++j)
      EXPECT_EQ(parsed(i)(j), original(i)(j))
        << "Mismatch at row " << i << ", col " << j;
  }
}
 
//============================================================================
// Edge Cases Tests
//============================================================================
 
class CsvEdgeCasesTest : public ::testing::Test {};
 
TEST_F(CsvEdgeCasesTest, OnlyNewlines)
{
  std::istringstream ss("\n\n\n");
  Array<Array<std::string>> data = csv_read_all(ss);
  
  // Each newline produces an empty row with one empty field
  EXPECT_GE(data.size(), 1u);
}
 
TEST_F(CsvEdgeCasesTest, OnlyDelimiters)
{
  std::string line = ",,,";
  Array<std::string> row = csv_read_row(line);
  
  // Four fields (three delimiters = four empty fields)
  ASSERT_EQ(row.size(), 4u);
  for (size_t i = 0; i < row.size(); ++i)
    EXPECT_EQ(row(i), "");
}
 
TEST_F(CsvEdgeCasesTest, EmptyQuotedField)
{
  std::string line = "a,\"\",b";
  Array<std::string> row = csv_read_row(line);
  
  ASSERT_EQ(row.size(), 3u);
  EXPECT_EQ(row(0), "a");
  EXPECT_EQ(row(1), "");
  EXPECT_EQ(row(2), "b");
}
 
TEST_F(CsvEdgeCasesTest, QuotedFieldWithOnlyQuotes)
{
  std::string line = "\"\"\"\"";  // Field containing single quote
  Array<std::string> row = csv_read_row(line);
  
  ASSERT_EQ(row.size(), 1u);
  EXPECT_EQ(row(0), "\"");
}
 
TEST_F(CsvEdgeCasesTest, VeryLongField)
{
  std::string long_string(10000, 'x');
  std::string line = "a," + long_string + ",b";
  Array<std::string> row = csv_read_row(line);
  
  ASSERT_EQ(row.size(), 3u);
  EXPECT_EQ(row(1), long_string);
}
 
TEST_F(CsvEdgeCasesTest, ManyColumns)
{
  std::string line;
  for (int i = 0; i < 100; ++i)
  {
    if (i > 0) line += ",";
    line += std::to_string(i);
  }
  
  Array<std::string> row = csv_read_row(line);
  
  ASSERT_EQ(row.size(), 100u);
  EXPECT_EQ(row(0), "0");
  EXPECT_EQ(row(99), "99");
}
 
TEST_F(CsvEdgeCasesTest, UnicodeContent)
{
  std::string line = "日本語,中文,한국어";
  Array<std::string> row = csv_read_row(line);
  
  ASSERT_EQ(row.size(), 3u);
  EXPECT_EQ(row(0), "日本語");
  EXPECT_EQ(row(1), "中文");
  EXPECT_EQ(row(2), "한국어");
}
 
//============================================================================
// Integration Tests
//============================================================================
 
TEST(CsvIntegrationTest, TypicalWorkflow)
{
  // 1. Parse CSV header and data
  std::istringstream input(
    "id,name,price,quantity\n"
    "1,Widget,9.99,100\n"
    "2,\"Gadget, Pro\",19.99,50\n"
    "3,\"Thing \"\"Deluxe\"\"\",29.99,25\n"
  );
  
  Array<Array<std::string>> data = csv_read_all(input);
  
  // 2. Verify structure
  ASSERT_EQ(data.size(), 4u);
  EXPECT_TRUE(csv_is_rectangular(data));
  
  // 3. Access header
  EXPECT_EQ(data(0)(0), "id");
  EXPECT_EQ(data(0)(1), "name");
  EXPECT_EQ(data(0)(2), "price");
  EXPECT_EQ(data(0)(3), "quantity");
  
  // 4. Parse numeric data
  EXPECT_EQ(csv_to_number<int>(data(1)(0)), 1);
  EXPECT_DOUBLE_EQ(csv_to_number<double>(data(1)(2)), 9.99);
  EXPECT_EQ(csv_to_number<int>(data(1)(3)), 100);
  
  // 5. Handle special characters
  EXPECT_EQ(data(2)(1), "Gadget, Pro");
  EXPECT_EQ(data(3)(1), "Thing \"Deluxe\"");
  
  // 6. Extract a column
  Array<std::string> names = csv_get_column(data, 1);
  EXPECT_EQ(names(1), "Widget");
  EXPECT_EQ(names(2), "Gadget, Pro");
}
 
//============================================================================
// Type Traits Tests
//============================================================================
 
TEST(CsvTypeTraits, NoDiscardAttribute)
{
  // Verify [[nodiscard]] attribute is respected
  EXPECT_TRUE((std::is_same<decltype(csv_num_columns(std::declval<Array<std::string>&>())), size_t>::value));
  EXPECT_TRUE((std::is_same<decltype(csv_is_rectangular(std::declval<Array<Array<std::string>>&>())), bool>::value));
}
 
//============================================================================
// CsvRow Tests
//============================================================================
 
class CsvRowTest : public ::testing::Test {};
 
TEST_F(CsvRowTest, IndexAccess)
{
  Array<std::string> fields;
  fields.append("a");
  fields.append("b");
  fields.append("c");
  
  CsvRow row(fields);
  
  EXPECT_EQ(row[0], "a");
  EXPECT_EQ(row[1], "b");
  EXPECT_EQ(row[2], "c");
}
 
TEST_F(CsvRowTest, HeaderAccess)
{
  Array<std::string> header;
  header.append("name");
  header.append("age");
  header.append("city");
  
  Array<std::string> fields;
  fields.append("Alice");
  fields.append("30");
  fields.append("NYC");
  
  CsvRow row(fields, header);
  
  EXPECT_EQ(row["name"], "Alice");
  EXPECT_EQ(row["age"], "30");
  EXPECT_EQ(row["city"], "NYC");
}
 
TEST_F(CsvRowTest, HeaderAccessThrowsWithoutHeader)
{
  Array<std::string> fields;
  fields.append("value");
  
  CsvRow row(fields);
  
  EXPECT_THROW((void)row["column"], std::runtime_error);
}
 
TEST_F(CsvRowTest, HeaderAccessThrowsForUnknownColumn)
{
  Array<std::string> header;
  header.append("name");
  
  Array<std::string> fields;
  fields.append("Alice");
  
  CsvRow row(fields, header);
  
  EXPECT_THROW((void)row["unknown"], std::out_of_range);
}
 
TEST_F(CsvRowTest, HasColumn)
{
  Array<std::string> header;
  header.append("name");
  header.append("age");
  
  Array<std::string> fields;
  fields.append("Alice");
  fields.append("30");
  
  CsvRow row(fields, header);
  
  EXPECT_TRUE(row.has_column("name"));
  EXPECT_TRUE(row.has_column("age"));
  EXPECT_FALSE(row.has_column("unknown"));
}
 
TEST_F(CsvRowTest, GetNumeric)
{
  Array<std::string> header;
  header.append("name");
  header.append("value");
  
  Array<std::string> fields;
  fields.append("test");
  fields.append("42");
  
  CsvRow row(fields, header);
  
  EXPECT_EQ(row.get<int>(1), 42);
  EXPECT_EQ(row.get<int>("value"), 42);
}
 
TEST_F(CsvRowTest, SizeAndEmpty)
{
  Array<std::string> fields;
  CsvRow empty_row(fields);
  EXPECT_TRUE(empty_row.empty());
  EXPECT_EQ(empty_row.size(), 0u);
  
  fields.append("a");
  CsvRow non_empty(fields);
  EXPECT_FALSE(non_empty.empty());
  EXPECT_EQ(non_empty.size(), 1u);
}
 
//============================================================================
// CsvReader Tests
//============================================================================
 
class CsvReaderTest : public ::testing::Test
{
protected:
  void SetUp() override
  {
    test_filename = "/tmp/aleph_csv_reader_test_" + std::to_string(rand()) + ".csv";
    
    // Create test file
    std::ofstream file(test_filename);
    file << "name,age,city\n";
    file << "Alice,30,NYC\n";
    file << "Bob,25,LA\n";
    file << "Charlie,35,Chicago\n";
    file.close();
  }
  
  void TearDown() override
  {
    std::remove(test_filename.c_str());
  }
  
  std::string test_filename;
};
 
TEST_F(CsvReaderTest, ReadWithHeader)
{
  CsvReader reader(test_filename);
  reader.read_header();
  
  EXPECT_TRUE(reader.has_header());
  EXPECT_EQ(reader.header().size(), 3u);
  EXPECT_EQ(reader.header()(0), "name");
}
 
TEST_F(CsvReaderTest, ReadRows)
{
  CsvReader reader(test_filename);
  reader.read_header();
  
  EXPECT_TRUE(reader.has_next());
  
  CsvRow row1 = reader.next_row();
  EXPECT_EQ(row1["name"], "Alice");
  EXPECT_EQ(row1["age"], "30");
  
  CsvRow row2 = reader.next_row();
  EXPECT_EQ(row2["name"], "Bob");
  
  CsvRow row3 = reader.next_row();
  EXPECT_EQ(row3["name"], "Charlie");
  
  EXPECT_FALSE(reader.has_next());
}
 
TEST_F(CsvReaderTest, Skip)
{
  CsvReader reader(test_filename);
  reader.read_header();
  reader.skip(1);  // Skip Alice
  
  CsvRow row = reader.next_row();
  EXPECT_EQ(row["name"], "Bob");
}
 
TEST_F(CsvReaderTest, RowsRead)
{
  CsvReader reader(test_filename);
  reader.read_header();
  
  EXPECT_EQ(reader.rows_read(), 0u);
  reader.next();
  EXPECT_EQ(reader.rows_read(), 1u);
  reader.next();
  EXPECT_EQ(reader.rows_read(), 2u);
}
 
TEST_F(CsvReaderTest, RangeBasedFor)
{
  CsvReader reader(test_filename);
  reader.read_header();
  
  size_t count = 0;
  for (const auto & row : reader)
  {
    (void)row;
    ++count;
  }
  
  EXPECT_EQ(count, 3u);
}
 
TEST_F(CsvReaderTest, FromStream)
{
  std::istringstream ss("a,b\n1,2\n");
  CsvReader reader(ss);
  
  Array<std::string> row1 = reader.next();
  EXPECT_EQ(row1(0), "a");
  
  Array<std::string> row2 = reader.next();
  EXPECT_EQ(row2(0), "1");
}
 
//============================================================================
// Filter and Selection Tests
//============================================================================
 
class CsvFilterTest : public ::testing::Test
{
protected:
  void SetUp() override
  {
    std::istringstream ss("name,status\nAlice,active\nBob,inactive\nCharlie,active\n");
    data = csv_read_all(ss);
  }
  
  Array<Array<std::string>> data;
};
 
TEST_F(CsvFilterTest, FilterByPredicate)
{
  auto result = csv_filter(data, [](const Array<std::string> & row) {
    return row.size() > 1 and row(1) == "active";
  });
  
  EXPECT_EQ(result.size(), 2u);  // Alice and Charlie
}
 
TEST_F(CsvFilterTest, FilterByValue)
{
  auto result = csv_filter_by_value(data, 1, "active");
  
  EXPECT_EQ(result.size(), 2u);
}
 
TEST_F(CsvFilterTest, SelectColumns)
{
  Array<size_t> cols;
  cols.append(0);  // name only
  
  auto result = csv_select_columns(data, cols);
  
  EXPECT_EQ(result.size(), data.size());
  EXPECT_EQ(result(0).size(), 1u);
  EXPECT_EQ(result(0)(0), "name");
}
 
TEST_F(CsvFilterTest, SkipRows)
{
  auto result = csv_skip_rows(data, 1);  // Skip header
  
  EXPECT_EQ(result.size(), 3u);
  EXPECT_EQ(result(0)(0), "Alice");
}
 
TEST_F(CsvFilterTest, TakeRows)
{
  auto result = csv_take_rows(data, 2);  // Header + Alice
  
  EXPECT_EQ(result.size(), 2u);
  EXPECT_EQ(result(1)(0), "Alice");
}
 
//============================================================================
// Statistics Tests
//============================================================================
 
class CsvStatisticsTest : public ::testing::Test
{
protected:
  void SetUp() override
  {
    std::istringstream ss("a,b,c\n1,,3\n4,5,\n7,8,9\n");
    data = csv_read_all(ss);
  }
  
  Array<Array<std::string>> data;
};
 
TEST_F(CsvStatisticsTest, CountRows)
{
  EXPECT_EQ(csv_count_rows(data), 4u);
}
 
TEST_F(CsvStatisticsTest, CountEmpty)
{
  EXPECT_EQ(csv_count_empty(data), 2u);  // Two empty fields
}
 
TEST_F(CsvStatisticsTest, CountIf)
{
  auto count = csv_count_if(data, [](const Array<std::string> & row) {
    return row.size() >= 3 and row(2) == "";
  });
  
  EXPECT_EQ(count, 1u);  // Row "4,5,"
}
 
TEST_F(CsvStatisticsTest, FindRow)
{
  auto idx = csv_find_row(data, [](const Array<std::string> & row) {
    return row.size() > 0 and row(0) == "4";
  });
  
  EXPECT_EQ(idx, 2u);
}
 
TEST_F(CsvStatisticsTest, FindByValue)
{
  auto idx = csv_find_by_value(data, 0, "7");
  EXPECT_EQ(idx, 3u);
}
 
TEST_F(CsvStatisticsTest, FindNotFound)
{
  auto idx = csv_find_by_value(data, 0, "xyz");
  EXPECT_EQ(idx, data.size());  // Not found
}
 
TEST_F(CsvStatisticsTest, Distinct)
{
  std::istringstream ss("cat\ndog\ncat\nbird\ndog\n");
  auto animals = csv_read_all(ss);
  
  auto unique = csv_distinct(animals, 0);
  EXPECT_EQ(unique.size(), 3u);  // cat, dog, bird
}
 
//============================================================================
// Transformation Tests
//============================================================================
 
class CsvTransformationTest : public ::testing::Test
{
protected:
  void SetUp() override
  {
    std::istringstream ss("a,b,c\n1,2,3\n4,5,6\n");
    data = csv_read_all(ss);
  }
  
  Array<Array<std::string>> data;
};
 
TEST_F(CsvTransformationTest, Transpose)
{
  auto result = csv_transpose(data);
  
  EXPECT_EQ(result.size(), 3u);   // 3 columns become 3 rows
  EXPECT_EQ(result(0).size(), 3u);  // 3 rows become 3 columns
  EXPECT_EQ(result(0)(0), "a");
  EXPECT_EQ(result(0)(1), "1");
  EXPECT_EQ(result(0)(2), "4");
}
 
TEST_F(CsvTransformationTest, SortByColumn)
{
  std::istringstream ss("charlie,3\nalice,1\nbob,2\n");
  auto unsorted = csv_read_all(ss);
  
  auto sorted = csv_sort_by_column(unsorted, 0);  // Sort by name
  
  EXPECT_EQ(sorted(0)(0), "alice");
  EXPECT_EQ(sorted(1)(0), "bob");
  EXPECT_EQ(sorted(2)(0), "charlie");
}
 
TEST_F(CsvTransformationTest, SortByColumnNumeric)
{
  std::istringstream ss("charlie,30\nalice,10\nbob,20\n");
  auto unsorted = csv_read_all(ss);
  
  auto sorted = csv_sort_by_column_numeric<int>(unsorted, 1);  // Sort by value
  
  EXPECT_EQ(sorted(0)(0), "alice");   // 10
  EXPECT_EQ(sorted(1)(0), "bob");     // 20
  EXPECT_EQ(sorted(2)(0), "charlie"); // 30
}
 
TEST_F(CsvTransformationTest, Unique)
{
  std::istringstream ss("a,b\n1,2\n3,4\n1,2\n5,6\n1,2\n");
  auto with_dupes = csv_read_all(ss);
  
  auto unique = csv_unique(with_dupes);
  
  EXPECT_EQ(unique.size(), 4u);  // header + 3 unique data rows
}
 
TEST_F(CsvTransformationTest, Transform)
{
  auto upper = csv_transform(data, [](const std::string & s) {
    std::string result = s;
    for (char & c : result)
      c = std::toupper(static_cast<unsigned char>(c));
    return result;
  });
  
  EXPECT_EQ(upper(0)(0), "A");
  EXPECT_EQ(upper(0)(1), "B");
}
 
TEST_F(CsvTransformationTest, AddColumn)
{
  auto with_sum = csv_add_column(data, [](const Array<std::string> & row) {
    if (row.size() < 3) return std::string("N/A");
    try {
      int sum = std::stoi(row(0)) + std::stoi(row(1)) + std::stoi(row(2));
      return std::to_string(sum);
    } catch (...) {
      return std::string("N/A");
    }
  });
  
  EXPECT_EQ(with_sum(0).size(), 4u);  // Original 3 + new column
  EXPECT_EQ(with_sum(1)(3), "6");     // 1+2+3
  EXPECT_EQ(with_sum(2)(3), "15");    // 4+5+6
}
 
TEST_F(CsvTransformationTest, RenameColumn)
{
  auto renamed = csv_rename_column(data, "a", "first_col");
  
  EXPECT_EQ(renamed(0)(0), "first_col");
  EXPECT_EQ(renamed(0)(1), "b");  // Unchanged
}
 
//============================================================================
// Utility Tests
//============================================================================
 
class CsvUtilityTest : public ::testing::Test {};
 
TEST_F(CsvUtilityTest, SkipBom)
{
  // Create stream with UTF-8 BOM (3 bytes: EF BB BF)
  std::string bom_str;
  bom_str += '\xEF';
  bom_str += '\xBB';
  bom_str += '\xBF';
  bom_str += "a,b,c\n";
  std::istringstream ss(bom_str);
  
  EXPECT_TRUE(csv_skip_bom(ss));
  
  auto row = csv_read_row(ss);
  EXPECT_EQ(row(0), "a");
}
 
TEST_F(CsvUtilityTest, SkipBomNotPresent)
{
  std::istringstream ss("a,b,c\n");
  
  EXPECT_FALSE(csv_skip_bom(ss));
  
  auto row = csv_read_row(ss);
  EXPECT_EQ(row(0), "a");  // Still reads correctly
}
 
TEST_F(CsvUtilityTest, TrimFields)
{
  std::istringstream ss("  a  ,  b  ,  c  \n");
  auto data = csv_read_all(ss);
  
  auto trimmed = csv_trim_fields(data);
  
  EXPECT_EQ(trimmed(0)(0), "a");
  EXPECT_EQ(trimmed(0)(1), "b");
  EXPECT_EQ(trimmed(0)(2), "c");
}
 
TEST_F(CsvUtilityTest, FillEmpty)
{
  std::istringstream ss("a,,c\n");
  auto data = csv_read_all(ss);
  
  auto filled = csv_fill_empty(data, "N/A");
  
  EXPECT_EQ(filled(0)(0), "a");
  EXPECT_EQ(filled(0)(1), "N/A");
  EXPECT_EQ(filled(0)(2), "c");
}
 
//============================================================================
// Join Tests
//============================================================================
 
class CsvJoinTest : public ::testing::Test {};
 
TEST_F(CsvJoinTest, JoinHorizontal)
{
  std::istringstream ss1("a,b\n1,2\n");
  std::istringstream ss2("c,d\n3,4\n");
  
  auto left = csv_read_all(ss1);
  auto right = csv_read_all(ss2);
  
  auto joined = csv_join_horizontal(left, right);
  
  EXPECT_EQ(joined.size(), 2u);
  EXPECT_EQ(joined(0).size(), 4u);
  EXPECT_EQ(joined(0)(0), "a");
  EXPECT_EQ(joined(0)(2), "c");
}
 
TEST_F(CsvJoinTest, JoinVertical)
{
  std::istringstream ss1("a,b\n1,2\n");
  std::istringstream ss2("3,4\n5,6\n");
  
  auto top = csv_read_all(ss1);
  auto bottom = csv_read_all(ss2);
  
  auto joined = csv_join_vertical(top, bottom);
  
  EXPECT_EQ(joined.size(), 4u);
  EXPECT_EQ(joined(2)(0), "3");
}
 
TEST_F(CsvJoinTest, InnerJoin)
{
  std::istringstream ss1("id,name\n1,Alice\n2,Bob\n3,Charlie\n");
  std::istringstream ss2("id,dept\n1,Sales\n3,Engineering\n4,HR\n");
  
  auto left = csv_read_all(ss1);
  auto right = csv_read_all(ss2);
  
  // Skip headers for join
  auto left_data = csv_skip_rows(left, 1);
  auto right_data = csv_skip_rows(right, 1);
  
  auto joined = csv_inner_join(left_data, 0, right_data, 0);
  
  EXPECT_EQ(joined.size(), 2u);  // Only 1 and 3 match
  EXPECT_EQ(joined(0)(1), "Alice");
  EXPECT_EQ(joined(0)(2), "Sales");
}
 
TEST_F(CsvJoinTest, GroupBy)
{
  std::istringstream ss("dept,name\nSales,Alice\nEng,Bob\nSales,Charlie\nEng,Dave\n");
  auto data = csv_read_all(ss);
  auto data_rows = csv_skip_rows(data, 1);
  
  auto groups = csv_group_by(data_rows, 0);
  
  EXPECT_EQ(groups.size(), 2u);  // Sales and Eng
  
  // Each group should have 2 members
  EXPECT_EQ(groups(0).size(), 2u);
  EXPECT_EQ(groups(1).size(), 2u);
}
 
//============================================================================
// Main
//============================================================================
 
int main(int argc, char **argv)
{
  ::testing::InitGoogleTest(&argc, argv);
  return RUN_ALL_TESTS();
}