description: You are given strings S and T, consisting of lowercase English letters. It is guaranteed that T is a permutation of the string abc. 
  
  Find string S', the lexicographically smallest permutation of S such that T is not a subsequence of S'.
  
  String a is a permutation of string b if the number of occurrences of each distinct character is the same in both strings.
  
  A string a is a subsequence of a string b if a can be obtained from b by deletion of several (possibly, zero or all) elements.
  
  A string a is lexicographically smaller than a string b if and only if one of the following holds:
  
    * a is a prefix of b, but a ≠ b;
    * in the first position where a and b differ, the string a has a letter that appears earlier in the alphabet than the corresponding letter in b.
  
  Input
  
  Each test contains multiple test cases. The first line contains a single integer t (1 ≤ t ≤ 1000) — the number of test cases. Description of the test cases follows.
  
  The first line of each test case contains a string S (1 ≤ |S| ≤ 100), consisting of lowercase English letters.
  
  The second line of each test case contains a string T that is a permutation of the string abc. (Hence, |T| = 3).
  
  Note that there is no limit on the sum of |S| across all test cases.
  
  Output
  
  For each test case, output a single string S', the lexicographically smallest permutation of S such that T is not a subsequence of S'.
  
  Example
  
  Input
  
  
  7
  abacaba
  abc
  cccba
  acb
  dbsic
  bac
  abracadabra
  abc
  dddddddddddd
  cba
  bbc
  abc
  ac
  abc
  
  
  Output
  
  
  aaaacbb
  abccc
  bcdis
  aaaaacbbdrr
  dddddddddddd
  bbc
  ac
  
  Note
  
  In the first test case, both aaaabbc and aaaabcb are lexicographically smaller than aaaacbb, but they contain abc as a subsequence.
  
  In the second test case, abccc is the smallest permutation of cccba and does not contain acb as a subsequence.
  
  In the third test case, bcdis is the smallest permutation of dbsic and does not contain bac as a subsequence.
solution: import array
  import bisect
  import heapq
  import math
  import collections
  import sys
  import copy
  from functools import reduce
  import decimal
  from io import BytesIO, IOBase
  import os
  import itertools
  import functools
  from types import GeneratorType
  
  #
  # sys.setrecursionlimit(10 ** 9)
  decimal.getcontext().rounding = decimal.ROUND_HALF_UP
  
  graphDict = collections.defaultdict
  
  queue = collections.deque
  
  
  ################## pypy deep recursion handling ##############
  # Author = @pajenegod
  def bootstrap(f, stack=[]):
      def wrappedfunc(*args, **kwargs):
          to = f(*args, **kwargs)
          if stack:
              return to
          else:
              while True:
                  if type(to) is GeneratorType:
                      stack.append(to)
                      to = next(to)
                  else:
                      stack.pop()
                      if not stack:
                          return to
                      to = stack[-1].send(to)
  
      return wrappedfunc
  
  
  ################## Graphs ###################
  class Graphs:
      def __init__(self):
          self.graph = graphDict(set)
  
      def add_edge(self, u, v):
          self.graph[u].add(v)
          self.graph[v].add(u)
  
      def dfs_utility(self, nodes, visited_nodes, colors, parity, level):
          global count
          if nodes == 1:
              colors[nodes] = -1
          else:
              if len(self.graph[nodes]) == 1 and parity % 2 == 0:
                  if q == 1:
                      colors[nodes] = 1
                  else:
                      colors[nodes] = -1
                      count += 1
              else:
                  if parity % 2 == 0:
                      colors[nodes] = -1
                  else:
                      colors[nodes] = 1
          visited_nodes.add(nodes)
          for neighbour in self.graph[nodes]:
              new_level = level + 1
              if neighbour not in visited_nodes:
                  self.dfs_utility(neighbour, visited_nodes, colors, level - 1, new_level)
  
      def dfs(self, node):
          Visited = set()
          color = collections.defaultdict()
          self.dfs_utility(node, Visited, color, 0, 0)
          return color
  
      def bfs(self, node, f_node):
          count = float("inf")
          visited = set()
          level = 0
          if node not in visited:
              queue.append([node, level])
              visited.add(node)
          flag = 0
          while queue:
              parent = queue.popleft()
              if parent[0] == f_node:
                  flag = 1
                  count = min(count, parent[1])
              level = parent[1] + 1
              for item in self.graph[parent[0]]:
                  if item not in visited:
                      queue.append([item, level])
                      visited.add(item)
          return count if flag else -1
          return False
  
  
  ################### Tree Implementaion ##############
  class Tree:
      def __init__(self, data):
          self.data = data
          self.left = None
          self.right = None
  
  
  def inorder(node, lis):
      if node:
          inorder(node.left, lis)
          lis.append(node.data)
          inorder(node.right, lis)
      return lis
  
  
  def leaf_node_sum(root):
      if root is None:
          return 0
      if root.left is None and root.right is None:
          return root.data
      return leaf_node_sum(root.left) + leaf_node_sum(root.right)
  
  
  def hight(root):
      if root is None:
          return -1
      if root.left is None and root.right is None:
          return 0
      return max(hight(root.left), hight(root.right)) + 1
  
  
  ################## Union Find #######################
  class UnionFind():
      parents = []
      sizes = []
      count = 0
  
      def __init__(self, n):
          self.count = n
          self.parents = [i for i in range(n)]
          self.sizes = [1 for i in range(n)]
  
      def find(self, i):
          if self.parents[i] == i:
              return i
          else:
              self.parents[i] = self.find(self.parents[i])
              return self.parents[i]
  
      def unite(self, i, j):
          root_i = self.find(i)
          root_j = self.find(j)
          if root_i == root_j:
              return
          elif root_i < root_j:
              self.parents[root_j] = root_i
              self.sizes[root_i] += self.sizes[root_j]
          else:
              self.parents[root_i] = root_j
              self.sizes[root_j] += self.sizes[root_i]
  
      def same(self, i, j):
          return self.find(i) == self.find(j)
  
      def size(self, i):
          return self.sizes[self.find(i)]
  
      def group_count(self):
          return len(set(self.find(i) for i in range(self.count)))
  
      def answer(self, extra, p, q):
          dic = collections.Counter()
          for q in range(n):
              dic[self.find(q)] = self.size(q)
          hq = list(dic.values())
          heapq._heapify_max(hq)
          ans = -1
          for z in range(extra + 1):
              if hq:
                  ans += heapq._heappop_max(hq)
              else:
                  break
          return ans
  
  
  #################################################
  
  def rounding(n):
      return int(decimal.Decimal(f'{n}').to_integral_value())
  
  
  def factors(n):
      return set(reduce(list.__add__,
                        ([i, n // i] for i in range(1, int(n ** 0.5) + 1) if n % i == 0)))
  
  
  def p_sum(array):
      return list(itertools.accumulate(array))
  
  
  def base_change(nn, bb):
      if nn == 0:
          return [0]
      digits = []
      while nn:
          digits.append(int(nn % bb))
          nn //= bb
      return digits[::-1]
  
  
  def diophantine(a: int, b: int, c: int):
      d, x, y = extended_gcd(a, b)
      r = c // d
      return r * x, r * y
  
  
  @bootstrap
  def extended_gcd(a: int, b: int):
      if b == 0:
          d, x, y = a, 1, 0
      else:
          (d, p, q) = yield extended_gcd(b, a % b)
          x = q
          y = p - q * (a // b)
  
      yield d, x, y
  
  
  ######################################################################################
  
  '''
  Knowledge and awareness are vague, and perhaps better called illusions.
  Everyone lives within their own subjective interpretation.
                                                              ~Uchiha Itachi
  '''
  
  ################################ <fast I/O> ###########################################
  BUFSIZE = 8192
  
  
  class FastIO(IOBase):
      newlines = 0
  
      def __init__(self, file):
          self._fd = file.fileno()
          self.buffer = BytesIO()
          self.writable = "x" in file.mode or "r" not in file.mode
          self.write = self.buffer.write if self.writable else None
  
      def read(self):
          while True:
              b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
              if not b:
                  break
              ptr = self.buffer.tell()
              self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
          self.newlines = 0
          return self.buffer.read()
  
      def readline(self, **kwargs):
          while self.newlines == 0:
              b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
              self.newlines = b.count(b"\n") + (not b)
              ptr = self.buffer.tell()
              self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
          self.newlines -= 1
          return self.buffer.readline()
  
      def flush(self):
          if self.writable:
              os.write(self._fd, self.buffer.getvalue())
              self.buffer.truncate(0), self.buffer.seek(0)
  
  
  class IOWrapper(IOBase):
      def __init__(self, file):
          self.buffer = FastIO(file)
          self.flush = self.buffer.flush
          self.writable = self.buffer.writable
          self.write = lambda s: self.buffer.write(s.encode("ascii"))
          self.read = lambda: self.buffer.read().decode("ascii")
          self.readline = lambda: self.buffer.readline().decode("ascii")
  
  
  sys.stdin, sys.stdout = IOWrapper(sys.stdin), IOWrapper(sys.stdout)
  
  
  #############################################<I/O Region >##############################################
  
  
  def inp():
      return sys.stdin.readline().strip()
  
  
  def map_inp(v_type):
      return map(v_type, inp().split())
  
  
  def list_inp(v_type):
      return list(map_inp(v_type))
  
  
  ######################################## Solution ####################################
  
  all_p = list(itertools.permutations(["a", "b", "c"]))
  all_p.sort()
  for _ in range(int(inp())):
      s = list(inp())
      t = list(inp())
      for item in all_p:
          if list(item) != t:
              t = queue(item)
              break
      dic = collections.Counter(s)
      if dic["a"] == 0 or dic["b"] == 0 or dic["c"] == 0:
          s.sort()
          print("".join(s))
      else:
          ans = ""
          order = list(dic.keys())
          order.sort()
          i = 0
          for item in order:
              if item in t:
                  x = t[i]
                  ans += x * dic[x]
                  i += 1
              else:
                  ans += item * dic[item]
          print(ans)
  