validate: validating against a JSONschema requires headers

src/cmd/validate.rs

@@ -97,9 +97,12 @@ Validate options:
 Common options:
     -h, --help                 Display this message
     -n, --no-headers           When set, the first row will not be interpreted
-                               as headers. Namely, it will be sorted with the rest
+                               as headers. It will be validated with the rest
                                of the rows. Otherwise, the first row will always
                                appear as the header row in the output.
+                               Note that this option is only valid when running
+                               in RFC 4180 validation mode as JSON Schema validation
+                               requires headers.
     -d, --delimiter <arg>      The field delimiter for reading CSV data.
                                Must be a single character. [default: ,]
     -p, --progressbar          Show progress bars. Not valid for stdin.
@@ -463,6 +466,12 @@ pub fn run(argv: &[&str]) -> CliResult<()> {
         return Ok(());
     }
 
+    // if we're here, we're validating with a JSON Schema
+    // JSONSchema validation requires headers
+    if args.flag_no_headers {
+        return fail_clierror!("Cannot validate CSV without headers against a JSON Schema.");
+    }
+
     // prep progress bar
     #[cfg(any(feature = "feature_capable", feature = "lite"))]
     let progress = ProgressBar::with_draw_target(None, ProgressDrawTarget::stderr_with_hz(5));

tests/test_validate.rs

@@ -304,6 +304,32 @@ fn validate_adur_public_toilets_dataset_with_json_schema_valid_output() {
     wrk.assert_err(&mut cmd);
 }
 
+#[test]
+fn validate_with_schema_noheader() {
+    let wrk = Workdir::new("validate_with_schema_noheader").flexible(true);
+
+    // copy schema file to workdir
+    let schema: String = wrk.load_test_resource("public-toilets-schema.json");
+    wrk.create_from_string("schema.json", &schema);
+
+    // copy csv file to workdir
+    let csv: String = wrk.load_test_resource("adur-public-toilets-valid.csv");
+    wrk.create_from_string("data.csv", &csv);
+
+    // run validate command
+    let mut cmd = wrk.command("validate");
+    cmd.arg("data.csv")
+        .arg("schema.json")
+        .arg("--no-headers")
+        .args(["--valid-output", "-"]);
+
+    let got = wrk.output_stderr(&mut cmd);
+    let expected = "Cannot validate CSV without headers against a JSON Schema.\n".to_string();
+    assert_eq!(got, expected);
+
+    wrk.assert_err(&mut cmd);
+}
+
 #[test]
 fn validate_adur_public_toilets_dataset_with_json_schema_url() {
     let wrk = Workdir::new("validate").flexible(true);