1 files changed, 139 insertions, 0 deletions
diff --git a/test/rubygems/package/tar_test_case.rb b/test/rubygems/package/tar_test_case.rb
new file mode 100644
index 0000000000..1161d0a5a8
--- /dev/null
+++ b/test/rubygems/package/tar_test_case.rb
@@ -0,0 +1,139 @@
+# frozen_string_literal: true
+require 'rubygems/test_case'
+require 'rubygems/package'
+
+##
+# A test case for Gem::Package::Tar* classes
+
+class Gem::Package::TarTestCase < Gem::TestCase
+  def ASCIIZ(str, length)
+    str + "\0" * (length - str.length)
+  end
+
+  def SP(s)
+    s + " "
+  end
+
+  def SP_Z(s)
+    s + " \0"
+  end
+
+  def Z(s)
+    s + "\0"
+  end
+
+  def assert_headers_equal(expected, actual)
+    expected = expected.to_s unless String === expected
+    actual = actual.to_s unless String === actual
+
+    fields = %w[
+      name 100
+      mode 8
+      uid 8
+      gid 8
+      size 12
+      mtime 12
+      checksum 8
+      typeflag 1
+      linkname 100
+      magic 6
+      version 2
+      uname 32
+      gname 32
+      devmajor 8
+      devminor 8
+      prefix 155
+    ]
+
+    offset = 0
+
+    until fields.empty? do
+      name = fields.shift
+      length = fields.shift.to_i
+
+      if name == "checksum"
+        chksum_off = offset
+        offset += length
+        next
+      end
+
+      assert_equal expected[offset, length], actual[offset, length],
+                   "Field #{name} of the tar header differs."
+
+      offset += length
+    end
+
+    assert_equal expected[chksum_off, 8], actual[chksum_off, 8]
+  end
+
+  def calc_checksum(header)
+    sum = header.unpack("C*").inject{|s,a| s + a }
+    SP(Z(to_oct(sum, 6)))
+  end
+
+  def header(type, fname, dname, length, mode, mtime, checksum = nil, linkname = "")
+    checksum ||= " " * 8
+
+    arr = [                  # struct tarfile_entry_posix
+      ASCIIZ(fname, 100),    # char name[100];     ASCII + (Z unless filled)
+      Z(to_oct(mode, 7)),    # char mode[8];       0 padded, octal null
+      Z(to_oct(0, 7)),       # char uid[8];        ditto
+      Z(to_oct(0, 7)),       # char gid[8];        ditto
+      Z(to_oct(length, 11)), # char size[12];      0 padded, octal, null
+      Z(to_oct(mtime, 11)),  # char mtime[12];     0 padded, octal, null
+      checksum,              # char checksum[8];   0 padded, octal, null, space
+      type,                  # char typeflag[1];   file: "0"  dir: "5"
+      ASCIIZ(linkname, 100), # char linkname[100]; ASCII + (Z unless filled)
+      "ustar\0",             # char magic[6];      "ustar\0"
+      "00",                  # char version[2];    "00"
+      ASCIIZ("wheel", 32),   # char uname[32];     ASCIIZ
+      ASCIIZ("wheel", 32),   # char gname[32];     ASCIIZ
+      Z(to_oct(0, 7)),       # char devmajor[8];   0 padded, octal, null
+      Z(to_oct(0, 7)),       # char devminor[8];   0 padded, octal, null
+      ASCIIZ(dname, 155), # char prefix[155];   ASCII + (Z unless filled)
+    ]
+
+    h = arr.join
+    ret = h + "\0" * (512 - h.size)
+    assert_equal(512, ret.size)
+    ret
+  end
+
+  def tar_dir_header(name, prefix, mode, mtime)
+    h = header("5", name, prefix, 0, mode, mtime)
+    checksum = calc_checksum(h)
+    header("5", name, prefix, 0, mode, mtime, checksum)
+  end
+
+  def tar_file_header(fname, dname, mode, length, mtime)
+    h = header("0", fname, dname, length, mode, mtime)
+    checksum = calc_checksum(h)
+    header("0", fname, dname, length, mode, mtime, checksum)
+  end
+
+  def tar_symlink_header(fname, prefix, mode, mtime, linkname)
+    h = header("2", fname, prefix, 0, mode, mtime, nil, linkname)
+    checksum = calc_checksum(h)
+    header("2", fname, prefix, 0, mode, mtime, checksum, linkname)
+  end
+
+  def to_oct(n, pad_size)
+    "%0#{pad_size}o" % n
+  end
+
+  def util_entry(tar)
+    io = TempIO.new tar
+
+    header = Gem::Package::TarHeader.from io
+
+    Gem::Package::TarReader::Entry.new header, io
+  end
+
+  def util_dir_entry
+    util_entry tar_dir_header("foo", "bar", 0, Time.now)
+  end
+
+  def util_symlink_entry
+    util_entry tar_symlink_header("foo", "bar", 0, Time.now, "link")
+  end
+end