#include <gtest/gtest.h>
#include <solution/392.h>

class IsSubsequenceTest : public ::testing::Test
{
  protected:
    void AssertIsSubsequence(const std::string &s, const std::string &t, bool expected)
    {
        char s_buf[1001], t_buf[1001];
        strncpy(s_buf, s.c_str(), sizeof(s_buf));
        s_buf[1000] = '\0';
        strncpy(t_buf, t.c_str(), sizeof(t_buf));
        t_buf[1000] = '\0';
        bool result = isSubsequence(s_buf, t_buf);
        EXPECT_EQ(result, expected);
    }
};

// 示例 1：s = "abc", t = "ahbgdc" → true
TEST_F(IsSubsequenceTest, Example1)
{
    AssertIsSubsequence("abc", "ahbgdc", true);
}

// 示例 2：s = "axc", t = "ahbgdc" → false
TEST_F(IsSubsequenceTest, Example2)
{
    AssertIsSubsequence("axc", "ahbgdc", false);
}

// 边界测试：s 为空 → 总是 true
TEST_F(IsSubsequenceTest, EmptyS)
{
    AssertIsSubsequence("", "anystring", true);
}

// 边界测试：t 为空 → 只有 s 也为空才为 true
TEST_F(IsSubsequenceTest, EmptyT)
{
    AssertIsSubsequence("a", "", false);
    AssertIsSubsequence("", "", true);
}

// s 比 t 长 → false
TEST_F(IsSubsequenceTest, SLongerThanT)
{
    AssertIsSubsequence("abcdefg", "abc", false);
}

// s 与 t 完全相同 → true
TEST_F(IsSubsequenceTest, SameString)
{
    AssertIsSubsequence("abcde", "abcde", true);
}

// 非连续但顺序正确 → true
TEST_F(IsSubsequenceTest, SparseSubsequence)
{
    AssertIsSubsequence("ace", "abcde", true);
}

// 非连续顺序错误 → false
TEST_F(IsSubsequenceTest, WrongOrder)
{
    AssertIsSubsequence("aec", "abcde", false);
}