add tests inspired from #2927

centered around -T# and --fast=# arguments

tests/playTests.sh

@@ -326,6 +326,51 @@ if [ "$isWindows" = false ] && [ "$UNAME" != "AIX" ]; then
   fi
 fi
 
+println "\n===>  multiple_thread test "
+
+datagen > tmp
+println "test : single-thread "
+zstd --fast --single-thread tmp -o tmpMT0
+println "test : one worker thread (default)"
+zstd --fast -T1 tmp -o tmpMT1
+println "test : two worker threads "
+zstd --fast -T2 tmp -o tmpMT2
+println "test : 16-thread "
+zstd --fast -T16 tmp -o tmpMT3
+println "test : 127-thread "
+zstd --fast -T127 tmp -o tmpMT4
+println "test : 128-thread "
+zstd --fast -T128 tmp -o tmpMT5
+println "test : max allowed numeric value is 4294967295 "
+zstd --fast -4294967295 tmp -o tmpMT6
+println "test : numeric value overflows 32-bit unsigned int "
+zstd --fast -4294967296 tmp -o tmptest9 && die "max allowed numeric value is 4294967295"
+
+datagen > tmp
+println "test : basic compression "
+zstd -f tmp  # trivial compression case, creates tmp.zst
+println "test : basic decompression"
+zstd -d -f -T1 tmp.zst
+println "note : decompression does not support -T mode, but execution support"
+rm -rf tmpMT*
+
+println "\n===>  --fast_argument test "
+datagen > tmp
+println "test : basic compression "
+zstd -f tmp  # trivial compression case, creates tmp.zst
+println "test: --fast=1"
+zstd --fast=1 -f tmp
+println "test: --fast=99"
+zstd --fast=99 -f tmp
+println "test: Invalid value -- negative number"
+zstd --fast=-1 -f tmp && die "error: Invalid value -- negative number"
+println "test: Invalid value -- zero"
+zstd --fast=0 -f tmp && die "error: Invalid value -- 0 number"
+println "test: max allowed numeric argument of --fast is 4294967295"
+zstd --fast=4294967295 -f tmp
+println "test: numeric value overflows 32-bit unsigned int "
+zstd --fast=4294967296 -f tmp && die "max allowed argument of --fast is 4294967295"
+
 println "\n===>  --exclude-compressed flag"
 rm -rf precompressedFilterTestDir
 mkdir -p precompressedFilterTestDir