patch-git: Add assert_eq function for internal testing

RPM-Changelog: -
RPM-Skip-Release: yes
Related: RHEL-111490

patch-git.lua

@@ -283,6 +283,137 @@ do
    end
 end
 
+-- Testing helper: assert_eq(a, b) asserts if not a == b.
+-- A third argument can be provided with a context string.
+local assert_eq
+do
+   -- quote(v) returns a string that evaluates to v, mostly in Lua syntax.
+   local quote
+   do
+      local quote_table = {
+         ['\n'] = '\\n',
+         ['\r'] = '\\r',
+         ['\t'] = '\\t',
+         ['\0'] = '\000',
+         ['"'] = '\\"',
+         ['\\'] = '\\\\',
+      }
+      local function quote_table_update(i)
+         local ch = string.char(i)
+         if quote_table[ch] == nil then
+            quote_table[ch] = string.format('\\x%02x', i)
+         end
+      end
+      for i=0,31 do
+         quote_table_update(i)
+      end
+      for i=127,255 do
+         quote_table_update(i)
+      end
+      local function quote1(v, seen)
+	 if v == nil then
+	    return 'nil'
+	 elseif v == true then
+	    return 'true'
+	 elseif v == false then
+	    return 'false'
+	 elseif type(v) == 'number' then
+	    return string.format('%q', v)
+	 elseif type(v) == 'string' then
+	    return '"' .. string.gsub(v, '.', quote_table) .. '"'
+	 elseif type(v) == 'table' then
+	    -- Prevent infinite recursion.
+	    local idx = seen[v]
+	    if idx then
+	       return '&' .. idx
+	    end
+	    local seen_count = seen[1] + 1
+	    seen[1] = seen_count
+	    seen[v] = seen_count
+
+	    local count = 0
+	    for _, _ in pairs(v) do
+	       count = count + 1
+	    end
+	    local result = {}
+	    if count == #v then
+	       -- Regular table.
+	       for i=1,count do
+		  result[i] = quote1(v[i], seen)
+	       end
+	    else
+	       -- Not a regular table.
+	       for key, value in pairs(v) do
+		  result[#result + 1] =
+		     '[' .. quote1(key, seen) .. ']='
+		     .. quote1(value, seen)
+	       end
+	    end
+	    return '{' .. table.concat(result, ', ') .. '}'
+	 else
+	    return '#<' .. type(v) .. ':' .. quote(tostring(v)) .. '>'
+	 end
+      end
+      function quote(v)
+	 return quote1(v, {0})
+      end
+   end
+   assert(quote('') == '""')
+   assert(quote('\n') == '"\\n"')
+   assert(quote('{}') == '"{}"')
+   assert(quote({}) == '{}')
+   assert(quote({1, 2, 3}) == '{1, 2, 3}')
+   assert(quote({a=1}) == '{["a"]=1}')
+
+   local deep_eq
+   do
+      local function deep_eq1(a, b, seen)
+	 if a == b then
+	    return true
+	 elseif type(a) == 'table' and type(b) == 'table' then
+	    assert(not seen[a])
+	    assert(not seen[b])
+	    seen[a] = true
+	    seen[b] = true
+	    local acount = 0
+	    for ak, av in pairs(a) do
+	       if not deep_eq1(av, b[ak], seen) then
+		  return false
+	       end
+	       acount = acount + 1
+	    end
+	    local bcount = 0
+	    for bk, bv in pairs(b) do
+	       bcount = bcount + 1
+	    end
+	    return acount == bcount
+	 else
+	    return false
+	 end
+      end
+      function deep_eq(a, b)
+	 if a == b then
+	    return true
+	 elseif type(a) == 'table' and type(b) == 'table' then
+	    return deep_eq1(a, b, {})
+	 end
+      end
+   end
+
+   function assert_eq(a, b, ctx)
+      if deep_eq(a, b) then
+	 return
+      end
+      local prefix
+      if ctx then
+	 prefix = ctx .. ': '
+      else
+	 prefix = ''
+      end
+      assert(a == b, prefix .. quote(a) .. ' ~= ' .. quote(b))
+   end
+end
+
 -- Sort the list lexicographically, in place, treating sequences of
 -- digits as a single positive decimal number.
 local function version_sort(list)