From a40e1e7692cbf3dc6f6e6a8c7229264d2e25fbec Mon Sep 17 00:00:00 2001
From: John Shumway <jshumway@amd.com>
Date: Fri, 19 Sep 2025 15:40:24 +0000
Subject: [PATCH] Add testing utils.

---
 experimental/builder/test/testing_utils.cpp | 104 ++++++++++++++++++++
 experimental/builder/test/testing_utils.hpp |  14 +++
 2 files changed, 118 insertions(+)
 create mode 100644 experimental/builder/test/testing_utils.cpp
 create mode 100644 experimental/builder/test/testing_utils.hpp

diff --git a/experimental/builder/test/testing_utils.cpp b/experimental/builder/test/testing_utils.cpp
new file mode 100644
index 0000000000..cd1cc8a173
--- /dev/null
+++ b/experimental/builder/test/testing_utils.cpp
@@ -0,0 +1,104 @@
+#include <string>
+#include <sstream>
+#include <vector>
+#include <algorithm>
+
+namespace ck_tile::test {
+
+// Copilot-generated diff function, seems to work great.
+// TODO: Study this, maybe add unit tests?
+//
+// This implementation is based on the Wagner-Fischer algorithm to find the
+// optimal edit script.
+std::string inlineDiff(const std::string& actual, const std::string& expected)
+{
+    const size_t n = expected.length();
+    const size_t m = actual.length();
+
+    std::vector<std::vector<int>> dp(n + 1, std::vector<int>(m + 1));
+
+    for(size_t i = 0; i <= n; ++i)
+    {
+        dp[i][0] = i;
+    }
+    for(size_t j = 0; j <= m; ++j)
+    {
+        dp[0][j] = j;
+    }
+
+    for(size_t i = 1; i <= n; ++i)
+    {
+        for(size_t j = 1; j <= m; ++j)
+        {
+            int cost = (expected[i - 1] == actual[j - 1]) ? 0 : 1;
+            dp[i][j] = std::min({dp[i - 1][j] + 1,        // Deletion
+                                 dp[i][j - 1] + 1,        // Insertion
+                                 dp[i - 1][j - 1] + cost}); // Substitution/Match
+        }
+    }
+
+    std::ostringstream diff;
+    std::string expected_diff, actual_diff;
+    bool in_diff = false;
+
+    size_t i = n, j = m;
+    while(i > 0 || j > 0)
+    {
+        int cost = (i > 0 && j > 0 && expected[i - 1] == actual[j - 1]) ? 0 : 1;
+
+        if(i > 0 && j > 0 && dp[i][j] == dp[i - 1][j - 1] + cost)
+        {
+            if(cost == 0)
+            {
+                if(in_diff)
+                {
+                    std::reverse(expected_diff.begin(), expected_diff.end());
+                    std::reverse(actual_diff.begin(), actual_diff.end());
+                    diff << "]" << expected_diff << "|" << actual_diff << "[";
+                    expected_diff.clear();
+                    actual_diff.clear();
+                    in_diff = false;
+                }
+                diff << expected[i - 1];
+            }
+            else
+            {
+                in_diff = true;
+                expected_diff += expected[i - 1];
+                actual_diff += actual[j - 1];
+            }
+            --i;
+            --j;
+        }
+        else if(j > 0 && dp[i][j] == dp[i][j - 1] + 1)
+        {
+            in_diff = true;
+            actual_diff += actual[j - 1];
+            --j;
+        }
+        else if(i > 0 && dp[i][j] == dp[i - 1][j] + 1)
+        {
+            in_diff = true;
+            expected_diff += expected[i - 1];
+            --i;
+        }
+    }
+
+    if(in_diff)
+    {
+        std::reverse(expected_diff.begin(), expected_diff.end());
+        std::reverse(actual_diff.begin(), actual_diff.end());
+        diff << "]" << expected_diff << "|" << actual_diff << "[]";
+    }
+
+    std::string result = diff.str();
+    std::reverse(result.begin(), result.end());
+    return result;
+}
+
+std::string formatInlineDiff(const std::string& actual, const std::string& expected)
+{
+    return std::string("Inline diff:  \"") + inlineDiff(actual, expected) + "\"";
+}
+
+} // namespace ck_tile::test
diff --git a/experimental/builder/test/testing_utils.hpp b/experimental/builder/test/testing_utils.hpp
new file mode 100644
index 0000000000..ba0c7f72f4
--- /dev/null
+++ b/experimental/builder/test/testing_utils.hpp
@@ -0,0 +1,14 @@
+#include <gtest/gtest.h>
+#include <string>
+#include <sstream>
+
+namespace ck_tile::test {
+
+// Returns a string highlighting differences between actual and expected.
+// Differences are enclosed in brackets with actual and expected parts separated by '|'.
+std::string inlineDiff(const std::string& actual, const std::string& expected);
+
+// A convenience alias for inlineDiff to improve readability in test assertions.
+std::string formatInlineDiff(const std::string& actual, const std::string& expected);
+
+} // namespace ck_tile::testing