diff: add option/flag --delimiter-output

src/cmd/diff.rs

@@ -16,6 +16,12 @@ Find the difference between two CSVs. The left CSV uses a tab as the delimiter:
     # or ';' as the delimiter
     qsv diff --delimiter-left ';' left.csv right-semicolon.csv
 
+Find the difference between two CSVs. The output CSV uses a tab as the delimiter
+and is written to a file:
+    qsv diff -o diff-tab.tsv --delimiter-output '\t' left.csv right.csv
+    # or ';' as the delimiter
+    qsv diff -o diff-semicolon.csv --delimiter-output ';' left.csv right.csv
+
 Find the difference between two CSVs, but only for the first two columns:
     qsv diff --key 0,1 left.csv right.csv
 
@@ -24,7 +30,7 @@ sort the result by the first and second column:
     qsv diff -k 0,1 --sort-columns 0,1 left.csv right.csv
 
 Find the difference between two CSVs, but do not output headers in the result:
-    qsv diff --no-headers-result left.csv right.csv
+    qsv diff --no-headers-output left.csv right.csv
 
 Find the difference between two CSVs. Both CSVs have no headers, but the result should have
 headers, so generic headers will be used in the form of: _col_1, _col_2, etc.:
@@ -45,13 +51,15 @@ diff options:
                                 the right CSV to diff. (When not set, the
                                 first row is the header row and will be skipped during
                                 the diff. It will always appear in the output.)
-    --no-headers-result         When set, the diff result won't have a header row in
+    --no-headers-output         When set, the diff result won't have a header row in
                                 it's output. If not set and both CSVs have no headers,
                                 headers in the result will be: _col_1,_col_2, etc.
     --delimiter-left <arg>      The field delimiter for reading CSV data on the left.
                                 Must be a single character. (default: ,)
     --delimiter-right <arg>     The field delimiter for reading CSV data on the right.
                                 Must be a single character. (default: ,)
+    --delimiter-output <arg>    The field delimiter for writing the CSV diff result.
+                                Must be a single character. (default: ,)
     -k, --key <arg...>          The column indices that uniquely identify a record
                                 as a comma separated list of indices, e.g. 0,1,2.
                                 (default: 0)
@@ -94,9 +102,10 @@ struct Args {
     flag_jobs:              Option<usize>,
     flag_no_headers_left:   bool,
     flag_no_headers_right:  bool,
+    flag_no_headers_output: bool,
     flag_delimiter_left:    Option<Delimiter>,
     flag_delimiter_right:   Option<Delimiter>,
-    flag_no_headers_result: bool,
+    flag_delimiter_output:  Option<Delimiter>,
     flag_key:               Option<String>,
     flag_sort_columns:      Option<String>,
 }
@@ -137,7 +146,9 @@ pub fn run(argv: &[&str]) -> CliResult<()> {
         })
         .transpose()?;
 
-    let wtr = Config::new(&args.flag_output).writer()?;
+    let wtr = Config::new(&args.flag_output)
+        .delimiter(args.flag_delimiter_output)
+        .writer()?;
     let csv_rdr_left = rconfig_left.reader()?;
     let csv_rdr_right = rconfig_right.reader()?;
 
@@ -166,7 +177,7 @@ pub fn run(argv: &[&str]) -> CliResult<()> {
         },
     }
 
-    let mut csv_diff_writer = CsvDiffWriter::new(wtr, args.flag_no_headers_result);
+    let mut csv_diff_writer = CsvDiffWriter::new(wtr, args.flag_no_headers_output);
     Ok(csv_diff_writer.write_diff_byte_records(diff_byte_records)?)
 }
 

tests/test_diff.rs

@@ -227,7 +227,7 @@ fn diff_with_no_headers_in_result() {
     wrk.create("right.csv", right);
 
     let mut cmd = wrk.command("diff");
-    cmd.args(["left.csv", "right.csv", "--no-headers-result"]);
+    cmd.args(["left.csv", "right.csv", "--no-headers-output"]);
 
     let got: Vec<Vec<String>> = wrk.read_stdout(&mut cmd);
     let expected = vec![
@@ -249,7 +249,7 @@ fn diff_no_diff_with_no_headers_in_result() {
     wrk.create("right.csv", right);
 
     let mut cmd = wrk.command("diff");
-    cmd.args(["left.csv", "right.csv", "--no-headers-result"]);
+    cmd.args(["left.csv", "right.csv", "--no-headers-output"]);
 
     let got: Vec<Vec<String>> = wrk.read_stdout(&mut cmd);
     let expected: Vec<Vec<String>> = vec![];
@@ -347,7 +347,7 @@ fn diff_with_no_left_no_right_and_no_headers_in_result() {
         "right.csv",
         "--no-headers-left",
         "--no-headers-right",
-        "--no-headers-result",
+        "--no-headers-output",
     ]);
 
     let got: Vec<Vec<String>> = wrk.read_stdout(&mut cmd);
@@ -425,6 +425,48 @@ fn diff_left_has_one_column_right_has_none_headers_in_result() {
     assert_eq!(got, expected);
 }
 
+#[test]
+fn diff_with_default_delimiter_in_result() {
+    let wrk = Workdir::new("diff_with_default_delimiter_in_result");
+
+    let left = vec![svec!["h1", "h2", "h3"], svec!["1", "foo", "bar"]];
+    wrk.create("left.csv", left);
+
+    let right = vec![svec!["h1", "h2", "h3"], svec!["1", "foo_changed", "bar"]];
+    wrk.create("right.csv", right);
+
+    let mut cmd = wrk.command("diff");
+    cmd.args(["left.csv", "right.csv"]);
+
+    let got: String = wrk.stdout(&mut cmd);
+    let expected = "\
+diffresult,h1,h2,h3
+-,1,foo,bar
++,1,foo_changed,bar";
+    assert_eq!(got.as_str(), expected);
+}
+
+#[test]
+fn diff_with_different_delimiter_in_result() {
+    let wrk = Workdir::new("diff_with_different_delimiter_in_result");
+
+    let left = vec![svec!["h1", "h2", "h3"], svec!["1", "foo", "bar"]];
+    wrk.create("left.csv", left);
+
+    let right = vec![svec!["h1", "h2", "h3"], svec!["1", "foo_changed", "bar"]];
+    wrk.create("right.csv", right);
+
+    let mut cmd = wrk.command("diff");
+    cmd.args(["left.csv", "right.csv", "--delimiter-output", ";"]);
+
+    let got: String = wrk.stdout(&mut cmd);
+    let expected = "\
+diffresult;h1;h2;h3
+-;1;foo;bar
++;1;foo_changed;bar";
+    assert_eq!(got.as_str(), expected);
+}
+
 fn create_file_with_delim(wrk: &Workdir, file_path_new: &str, file_path: &str, delimiter: u8) {
     let mut select_cmd = wrk.command("select");
     select_cmd.args(["1-", file_path]);