bringing in testkit tools

[feisty_meow.git] / testkit / library / file_management.sh

diff --git a/testkit/library/file_management.sh b/testkit/library/file_management.sh
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+
+# these are the pieces that we'll use to assemble mostly random files.
+RANDOM_CHUNK_FILES=($TEST_TEMP/random.0 $TEST_TEMP/random.1 $TEST_TEMP/random.2 $TEST_TEMP/random.3 $TEST_TEMP/random.4)
+
+# largest chunk of random data we'll actually generate at a time, in each chunk file.
+export MAX_CHUNK_FILE=65536
+
+# returns the file size for the first argument.
+function getFileSize()
+{
+  local file="$1"; shift
+  if isMacOSX; then
+    stat -f%z "$file"
+  else
+    stat --printf="%s" "$file"
+  fi
+}
+
+# outputs the number of seconds since the epoch.
+function getTimeStamp()
+{
+  date +%s
+}
+
+# makes sure the chunk files are all generated.
+function prepareRandomChunks()
+{
+  local i
+  for ((i = 0; i < ${#RANDOM_CHUNK_FILES[@]}; i++)); do
+    # make the chunk files if they don't exist.
+    local currfile="${RANDOM_CHUNK_FILES[$i]}"
+    if [ ! -f "$currfile" ]; then
+      local filesize=$MAX_CHUNK_FILE
+      # pick a value to add or subtract from the constant sized chunk, so we won't always be
+      # using files at the same boundaries or with a power of 2 size.
+      local moddy=$(( ($(echo $RANDOM) % 128) - 64 ))
+      ((filesize -= $moddy))
+#echo creating chunk file $currfile of size $filesize
+      dd if=/dev/urandom of=$currfile bs=1 count=$filesize &>/dev/null
+      assertEquals "creating random chunk file $currfile" 0 $?
+    fi
+  done
+}
+
+# creates a somewhat random file for testing.  this will be assembled out of
+# our chunks of random files, so is not truly random, but we've found that the
+# random number generator is a HUGE drag on our testing speed.  this is still
+# pretty random data.  the first argument is the file name and the second is
+# the desired file size.
+function createRandomFile()
+{
+  local file="$1"; shift
+  local size="$1"; shift
+
+  prepareRandomChunks
+
+  local stampBefore=$(getTimeStamp)
+
+  # truncate any existing stuff.
+  echo -n >"$file"
+
+  while [ $(getFileSize "$file") -lt $size ]; do
+    which_chunker=$(expr $(echo $RANDOM) % ${#RANDOM_CHUNK_FILES[@]})
+#echo choosing chunk file $which_chunker
+    cat "${RANDOM_CHUNK_FILES[$which_chunker]}" >>"$file"
+  done
+
+#echo file size after random chunkings is $(getFileSize "$file")
+
+  local fsizenow="$(getFileSize "$file")"
+#echo size now is $fsizenow and desired is $size
+  if [ $fsizenow -gt $size ]; then
+#echo trying to truncate file
+    truncate -s $size "$file"
+  fi
+#echo file size after truncate is $(getFileSize "$file") and expected size is $size
+
+  local stampAfter=$(getTimeStamp)
+  local secs=$(($stampAfter - $stampBefore))
+  if [ $secs -le 0 ]; then
+    # even though it claims it took zero time, we know better, but we also don't want to
+    # divide by zero, so it loses its credit for being very fast here.
+    secs=1
+  fi
+  local kbs=$(( $size / $secs / 1024))
+  
+  local fsizenow="$(getFileSize "$file")"
+  assertEquals "Creating random file of $size bytes at ${kbs} kbps in: $file" $size $fsizenow
+}
+