Add example tests (nu-plugin-test-support) for plugins in repo (#12281)

# Description

Uses the new `nu-plugin-test-support` crate to test the examples of
commands provided by plugins in the repo.

Also fixed some of the examples to pass.

# User-Facing Changes

- Examples that are more guaranteed to work

# Tests + Formatting
- 🟢 `toolkit fmt`
- 🟢 `toolkit clippy`
- 🟢 `toolkit test`
- 🟢 `toolkit test stdlib`

crates/nu_plugin_formats/src/from/eml.rs

@@ -53,6 +53,7 @@ pub fn examples() -> Vec<PluginExample> {
             example: "'From: test@email.com
 Subject: Welcome
 To: someone@somewhere.com
+
 Test' | from eml"
                 .into(),
             result: Some(Value::test_record(record! {
@@ -73,6 +74,7 @@ Test' | from eml"
             example: "'From: test@email.com
 Subject: Welcome
 To: someone@somewhere.com
+
 Test' | from eml -b 1"
                 .into(),
             result: Some(Value::test_record(record! {
@@ -164,3 +166,10 @@ fn from_eml(input: &Value, body_preview: usize, head: Span) -> Result<Value, Lab
 
     Ok(Value::record(collected.into_iter().collect(), head))
 }
+
+#[test]
+fn test_examples() -> Result<(), nu_protocol::ShellError> {
+    use nu_plugin_test_support::PluginTest;
+
+    PluginTest::new("formats", crate::FromCmds.into())?.test_command_examples(&FromEml)
+}

crates/nu_plugin_formats/src/from/ics.rs

@@ -75,8 +75,9 @@ impl SimplePluginCommand for FromIcs {
 
 pub fn examples() -> Vec<PluginExample> {
     vec![PluginExample {
-        example: "'BEGIN:VCALENDAR
-            END:VCALENDAR' | from ics"
+        example: "
+'BEGIN:VCALENDAR
+END:VCALENDAR' | from ics"
             .into(),
         description: "Converts ics formatted string to table".into(),
         result: Some(Value::test_list(vec![Value::test_record(record! {
@@ -263,3 +264,10 @@ fn params_to_value(params: Vec<(String, Vec<String>)>, span: Span) -> Value {
 
     Value::record(row.into_iter().collect(), span)
 }
+
+#[test]
+fn test_examples() -> Result<(), nu_protocol::ShellError> {
+    use nu_plugin_test_support::PluginTest;
+
+    PluginTest::new("formats", crate::FromCmds.into())?.test_command_examples(&FromIcs)
+}

crates/nu_plugin_formats/src/from/ini.rs

@@ -89,3 +89,10 @@ b=2' | from ini"
         })),
     }]
 }
+
+#[test]
+fn test_examples() -> Result<(), nu_protocol::ShellError> {
+    use nu_plugin_test_support::PluginTest;
+
+    PluginTest::new("formats", crate::FromCmds.into())?.test_command_examples(&FromIni)
+}

crates/nu_plugin_formats/src/from/vcf.rs

@@ -153,3 +153,10 @@ fn params_to_value(params: Vec<(String, Vec<String>)>, span: Span) -> Value {
 
     Value::record(row.into_iter().collect(), span)
 }
+
+#[test]
+fn test_examples() -> Result<(), nu_protocol::ShellError> {
+    use nu_plugin_test_support::PluginTest;
+
+    PluginTest::new("formats", crate::FromCmds.into())?.test_command_examples(&FromVcf)
+}