feat: add "file doesn't contain" step to lib/files, Python and Rust

Sponsored-by: author

4 files changed, 32 insertions, 0 deletions

diff --git a/share/common/lib/files.yaml b/share/common/lib/files.yaml
index cf85cfa..e4d9b6b 100644
--- a/share/common/lib/files.yaml
+++ b/share/common/lib/files.yaml
@@ -174,6 +174,14 @@
     python:
       function: files_file_contains
 
+- then: file (?P<filename>\S+) doesn't contain "(?P<data>.*)"
+  regex: true
+  impl:
+    rust:
+      function: subplotlib::steplibrary::files::file_doesnt_contain
+    python:
+      function: files_file_doesnt_contain
+
 - then: file (?P<filename>\S+) matches regex /(?P<regex>.*)/
   regex: true
   impl:
diff --git a/share/python/lib/files.py b/share/python/lib/files.py
index fe94ed2..3ea5877 100644
--- a/share/python/lib/files.py
+++ b/share/python/lib/files.py
@@ -85,6 +85,14 @@ def files_file_contains(ctx, filename=None, data=None):
     assert_eq(data in actual, True)
 
 
+def files_file_doesnt_contain(ctx, filename=None, data=None):
+    assert_eq = globals()["assert_eq"]
+    with open(filename, "rb") as f:
+        actual = f.read()
+        actual = actual.decode("UTF-8")
+    assert_eq(data in actual, False)
+
+
 def files_file_matches_regex(ctx, filename=None, regex=None):
     assert_eq = globals()["assert_eq"]
     with open(filename) as f:
diff --git a/subplotlib/src/steplibrary/files.rs b/subplotlib/src/steplibrary/files.rs
index fd84e1c..b94155f 100644
--- a/subplotlib/src/steplibrary/files.rs
+++ b/subplotlib/src/steplibrary/files.rs
@@ -232,6 +232,21 @@ pub fn file_contains(context: &Datadir, filename: &str, data: &str) {
     }
 }
 
+/// Check if a file lacks a given sequence of characters
+///
+/// # `then file (?P<filename>\S+) does not contain "(?P<data>.*)"`
+///
+/// This will load the content of the named file and ensure it lacks the given string.
+/// Note: this assumes everything is utf-8 encoded.  If not, things will fail.
+#[step]
+pub fn file_doesnt_contain(context: &Datadir, filename: &str, data: &str) {
+    let full_path = context.canonicalise_filename(filename)?;
+    let body = fs::read_to_string(full_path)?;
+    if body.contains(data) {
+        throw!("unexpected file content found");
+    }
+}
+
 /// Check if a file's content matches the given regular expression
 ///
 /// # `then file (?P<filename>\S+) matches regex /(?P<regex>.*)/`
diff --git a/tests/subplots/common/files.md b/tests/subplots/common/files.md
index 13d9874..d8d598b 100644
--- a/tests/subplots/common/files.md
+++ b/tests/subplots/common/files.md
@@ -67,6 +67,7 @@ These steps verify contents of files.
 ~~~scenario
 given file hello.txt
 then file hello.txt contains "hello, world"
+then file hello.txt doesn't contain "hello, sailor"
 and file hello.txt matches regex "hello, .*"
 and file hello.txt matches regex /hello, .*/
 ~~~