Merge pull request #632 from E3SM-Project/dqwu/test_compare_offsets

This PR adds additional test cases to ensure the internal comparison
function compare_offsets() correctly handles the differences between
64-bit offset values, including edge cases with extremely large or
small values.

The new test cases would fail with the current master branch, and
they are expected to be fixed by PR #631.

Author: dqwu

tests/cunit/test_rearr.c

@@ -8,6 +8,9 @@
 #include <pio.h>
 #include <pio_tests.h>
 #include <pio_internal.h>
+#if SIZEOF_PIO_OFFSET >= 8
+#include <stdint.h>
+#endif
 
 /* The number of tasks this test should run on. */
 #define TARGET_NTASKS 4
@@ -76,6 +79,9 @@ int test_rearranger_opts1(int iosysid)
 int test_compare_offsets()
 {
     mapsort m1, m2, m3;
+#if SIZEOF_PIO_OFFSET >= 8
+    mapsort m_max, m_min;
+#endif
 
     m1.rfrom = 0;
     m1.soffset = 0;
@@ -86,6 +92,14 @@ int test_compare_offsets()
     m3.rfrom = 0;
     m3.soffset = 0;
     m3.iomap = 1;
+#if SIZEOF_PIO_OFFSET >= 8
+    m_max.rfrom = 0;
+    m_max.soffset = 0;
+    m_max.iomap = INT64_MAX;
+    m_min.rfrom = 0;
+    m_min.soffset = 0;
+    m_min.iomap = INT64_MIN;
+#endif
 
     /* Return 0 if either or both parameters are null. */
     if (compare_offsets(NULL, &m2))
@@ -102,6 +116,35 @@ int test_compare_offsets()
     /* m1 and m3 are different. */
     if (compare_offsets(&m1, &m3) != -1)
         return ERR_WRONG;
+
+#if SIZEOF_PIO_OFFSET >= 8
+    /* Some representative test cases for 64-bit offset comparison with extreme values */
+
+    /* Test: INT64_MAX - INT64_MIN, expected to be positive */
+    if (compare_offsets(&m_max, &m_min) <= 0)
+        return ERR_WRONG;
+
+    /* Test: INT64_MIN - INT64_MAX, expected to be negative */
+    if (compare_offsets(&m_min, &m_max) >= 0)
+        return ERR_WRONG;
+
+    /* Test: INT64_MAX - 0, expected to be positive */
+    if (compare_offsets(&m_max, &m1) <= 0)
+        return ERR_WRONG;
+
+    /* Test: 0 - INT64_MAX, expected to be negative */
+    if (compare_offsets(&m1, &m_max) >= 0)
+        return ERR_WRONG;
+
+    /* Test: INT64_MIN - 0, expected to be negative */
+    if (compare_offsets(&m_min, &m1) >= 0)
+        return ERR_WRONG;
+
+    /* Test: 0 - INT64_MIN, expected to be positive */
+    if (compare_offsets(&m1, &m_min) <= 0)
+        return ERR_WRONG;
+#endif
+
     return 0;
 }