Fix find -v command on tables (issue #9043) (#9159)

# Description
This PR fixes issue #9043 where find -v was returning empty tables
and/or wrong output.
It also refactors some big code chunks with repetitions into it's own
functions.

# User-Facing Changes

# Tests + Formatting
Unit tests added for asserting changes.

# After Submitting

crates/nu-command/tests/commands/find.rs

@@ -1,123 +1,96 @@
-use nu_test_support::fs::Stub::EmptyFile;
-use nu_test_support::playground::Playground;
-use nu_test_support::{nu, pipeline};
+use nu_test_support::nu;
 
 #[test]
 fn find_with_list_search_with_string() {
-    let actual = nu!(
-    cwd: ".", pipeline(
-    r#"
-        [moe larry curly] | find moe | get 0
-    "#
-    ));
+    let actual = nu!("[moe larry curly] | find moe | get 0");
 
     assert_eq!(actual.out, "moe");
 }
 
 #[test]
 fn find_with_list_search_with_char() {
-    let actual = nu!(
-    cwd: ".", pipeline(
-    r#"
-        [moe larry curly] | find l | to json -r
-    "#
-    ));
+    let actual = nu!("[moe larry curly] | find l | to json -r");
 
     assert_eq!(actual.out, r#"["larry","curly"]"#);
 }
 
 #[test]
 fn find_with_list_search_with_number() {
-    let actual = nu!(
-    cwd: ".", pipeline(
-    r#"
-        [1 2 3 4 5] | find 3 | get 0
-    "#
-    ));
+    let actual = nu!("[1 2 3 4 5] | find 3 | get 0");
 
     assert_eq!(actual.out, "3");
 }
 
 #[test]
 fn find_with_string_search_with_string() {
-    let actual = nu!(
-    cwd: ".", pipeline(
-    r#"
-        echo Cargo.toml | find toml
-    "#
-    ));
+    let actual = nu!("echo Cargo.toml | find toml");
 
     assert_eq!(actual.out, "Cargo.toml");
 }
 
 #[test]
 fn find_with_string_search_with_string_not_found() {
-    let actual = nu!(
-    cwd: ".", pipeline(
-    r#"
-        [moe larry curly] | find shemp | is-empty
-    "#
-    ));
+    let actual = nu!("[moe larry curly] | find shemp | is-empty");
 
     assert_eq!(actual.out, "true");
 }
 
 #[test]
 fn find_with_filepath_search_with_string() {
-    Playground::setup("filepath_test_1", |dirs, sandbox| {
-        sandbox.with_files(vec![
-            EmptyFile("amigos.txt"),
-            EmptyFile("arepas.clu"),
-            EmptyFile("los.txt"),
-            EmptyFile("tres.txt"),
-        ]);
+    let actual =
+        nu!(r#"["amigos.txt","arepas.clu","los.txt","tres.txt"] | find arep | to json -r"#);
 
-        let actual = nu!(
-            cwd: dirs.test(), pipeline(
-            r#"
-                ls
-                | get name
-                | find arep
-                | to json -r
-            "#
-        ));
-
-        assert_eq!(actual.out, r#"["arepas.clu"]"#);
-    })
+    assert_eq!(actual.out, r#"["arepas.clu"]"#);
 }
 
 #[test]
 fn find_with_filepath_search_with_multiple_patterns() {
-    Playground::setup("filepath_test_2", |dirs, sandbox| {
-        sandbox.with_files(vec![
-            EmptyFile("amigos.txt"),
-            EmptyFile("arepas.clu"),
-            EmptyFile("los.txt"),
-            EmptyFile("tres.txt"),
-        ]);
+    let actual =
+        nu!(r#"["amigos.txt","arepas.clu","los.txt","tres.txt"] | find arep ami | to json -r"#);
 
-        let actual = nu!(
-            cwd: dirs.test(), pipeline(
-            r#"
-                ls
-                | get name
-                | find arep ami
-                | to json -r
-            "#
-        ));
-
-        assert_eq!(actual.out, r#"["amigos.txt","arepas.clu"]"#);
-    })
+    assert_eq!(actual.out, r#"["amigos.txt","arepas.clu"]"#);
 }
 
 #[test]
 fn find_takes_into_account_linebreaks_in_string() {
-    let actual = nu!(
-    cwd: ".", pipeline(
-    r#"
-        "atest\nanothertest\nnohit\n" | find a | length
-        "#
-    ));
+    let actual = nu!(r#""atest\nanothertest\nnohit\n" | find a | length"#);
 
     assert_eq!(actual.out, "2");
 }
+
+#[test]
+fn find_with_regex_in_table_keeps_row_if_one_column_matches() {
+    let actual = nu!(
+        "[[name nickname]; [Maurice moe] [Laurence larry]] | find --regex ce | get name | to json -r"
+    );
+
+    assert_eq!(actual.out, r#"["Maurice","Laurence"]"#);
+}
+
+#[test]
+fn inverted_find_with_regex_in_table_keeps_row_if_none_of_the_columns_matches() {
+    let actual = nu!(
+        "[[name nickname]; [Maurice moe] [Laurence larry]] | find --regex moe --invert | get name | to json -r"
+    );
+
+    assert_eq!(actual.out, r#"["Laurence"]"#);
+}
+
+#[test]
+fn find_in_table_only_keep_rows_with_matches_on_selected_columns() {
+    let actual = nu!(
+        "[[name nickname]; [Maurice moe] [Laurence larry]] | find r --columns [nickname] | get name | to json -r"
+    );
+
+    assert!(actual.out.contains("Laurence"));
+    assert!(!actual.out.contains("Maurice"));
+}
+
+#[test]
+fn inverted_find_in_table_keeps_row_if_none_of_the_selected_columns_matches() {
+    let actual = nu!(
+        "[[name nickname]; [Maurice moe] [Laurence larry]] | find r --columns [nickname] --invert | get name | to json -r"
+    );
+
+    assert_eq!(actual.out, r#"["Maurice"]"#);
+}