Added tests and updated doc

docs/utils.md

@@ -450,6 +450,9 @@ optional arguments:
                         useful if you are redirecting output to a file.
   --print-json          Print best result detailization in JSON format.
   --no-details          Do not print best epoch details.
+  --export-csv FILE     Export to CSV-File. Put + in front of filename to
+                        overwrite. This will disable table print. Example:
+                        --export-csv +hyperopt.csv
 
 Common arguments:
   -v, --verbose         Verbose mode (-vv for more, -vvv to get all messages).

freqtrade/commands/cli_options.py

@@ -224,6 +224,7 @@ AVAILABLE_CLI_OPTIONS = {
     "export_csv": Arg(
         '--export-csv',
         help='Export to CSV-File. Put + in front of filename to overwrite.'
+        ' This will disable table print.'
         ' Example: --export-csv +hyperopt.csv',
         metavar='FILE',
     ),

freqtrade/commands/hyperopt_commands.py

@@ -50,6 +50,7 @@ def start_hyperopt_list(args: Dict[str, Any]) -> None:
     if print_colorized:
         colorama_init(autoreset=True)
 
+    if not export_csv:
         try:
             Hyperopt.print_result_table(config, trials, total_epochs,
                                         not filteroptions['only_best'], print_colorized, 0)
@@ -60,7 +61,7 @@ def start_hyperopt_list(args: Dict[str, Any]) -> None:
         sorted_trials = sorted(trials, key=itemgetter('loss'))
         results = sorted_trials[0]
         Hyperopt.print_epoch_details(results, total_epochs, print_json, no_header)
-    print(export_csv)
+
     if trials and export_csv:
         overwrite_csv = False
         if export_csv[0] == '+':

tests/commands/test_commands.py

@@ -902,7 +902,21 @@ def test_hyperopt_list(mocker, capsys, hyperopt_results):
     assert all(x not in captured.out
                for x in [" 1/12", " 3/12", " 4/12", " 5/12", " 7/12", " 8/12"
                          " 9/12", " 10/12", " 11/12", " 12/12"])
-
+    args = [
+        "hyperopt-list",
+        "--no-details",
+        "--export-csv", "+test_file.csv"
+    ]
+    pargs = get_args(args)
+    pargs['config'] = None
+    start_hyperopt_list(pargs)
+    captured = capsys.readouterr()
+    assert all(x in captured.out
+               for x in ["CSV-File created!"])
+    f = Path("test_file.csv")
+    assert 'Best,1,2,-1.25%,-0.00125625,,-2.51,"3,930.0 m",0.43662' in f.read_text()
+    assert f.is_file()
+    f.unlink()
 
 def test_hyperopt_show(mocker, capsys, hyperopt_results):
     mocker.patch(