add tests

2 files changed, 126 insertions, 0 deletions

diff --git a/src/tools/compiletest/src/read2.rs b/src/tools/compiletest/src/read2.rs
index bd5f3593b65..313508a7966 100644
--- a/src/tools/compiletest/src/read2.rs
+++ b/src/tools/compiletest/src/read2.rs
@@ -1,6 +1,9 @@
 // FIXME: This is a complete copy of `cargo/src/cargo/util/read2.rs`
 // Consider unify the read2() in libstd, cargo and this to prevent further code duplication.
 
+#[cfg(test)]
+mod tests;
+
 pub use self::imp::read2;
 use std::io::{self, Write};
 use std::mem::replace;
diff --git a/src/tools/compiletest/src/read2/tests.rs b/src/tools/compiletest/src/read2/tests.rs
new file mode 100644
index 00000000000..d66b501fc2b
--- /dev/null
+++ b/src/tools/compiletest/src/read2/tests.rs
@@ -0,0 +1,123 @@
+use crate::read2::{ProcOutput, EXCLUDED_PLACEHOLDER_LEN, HEAD_LEN, TAIL_LEN};
+
+#[test]
+fn test_abbreviate_short_string() {
+    let mut out = ProcOutput::new();
+    out.extend(b"Hello world!", &[]);
+    assert_eq!(b"Hello world!", &*out.into_bytes());
+}
+
+#[test]
+fn test_abbreviate_short_string_multiple_steps() {
+    let mut out = ProcOutput::new();
+
+    out.extend(b"Hello ", &[]);
+    out.extend(b"world!", &[]);
+
+    assert_eq!(b"Hello world!", &*out.into_bytes());
+}
+
+#[test]
+fn test_abbreviate_long_string() {
+    let mut out = ProcOutput::new();
+
+    let data = vec![b'.'; HEAD_LEN + TAIL_LEN + 16];
+    out.extend(&data, &[]);
+
+    let mut expected = vec![b'.'; HEAD_LEN];
+    expected.extend_from_slice(b"\n\n<<<<<< SKIPPED 16 BYTES >>>>>>\n\n");
+    expected.extend_from_slice(&vec![b'.'; TAIL_LEN]);
+
+    // We first check the length to avoid endless terminal output if the length differs, since
+    // `out` is hundreds of KBs in size.
+    let out = out.into_bytes();
+    assert_eq!(expected.len(), out.len());
+    assert_eq!(expected, out);
+}
+
+#[test]
+fn test_abbreviate_long_string_multiple_steps() {
+    let mut out = ProcOutput::new();
+
+    out.extend(&vec![b'.'; HEAD_LEN], &[]);
+    out.extend(&vec![b'.'; TAIL_LEN], &[]);
+    // Also test whether the rotation works
+    out.extend(&vec![b'!'; 16], &[]);
+    out.extend(&vec![b'?'; 16], &[]);
+
+    let mut expected = vec![b'.'; HEAD_LEN];
+    expected.extend_from_slice(b"\n\n<<<<<< SKIPPED 32 BYTES >>>>>>\n\n");
+    expected.extend_from_slice(&vec![b'.'; TAIL_LEN - 32]);
+    expected.extend_from_slice(&vec![b'!'; 16]);
+    expected.extend_from_slice(&vec![b'?'; 16]);
+
+    // We first check the length to avoid endless terminal output if the length differs, since
+    // `out` is hundreds of KBs in size.
+    let out = out.into_bytes();
+    assert_eq!(expected.len(), out.len());
+    assert_eq!(expected, out);
+}
+
+#[test]
+fn test_abbreviate_exclusions_are_detected() {
+    let mut out = ProcOutput::new();
+    let exclusions = &["foo".to_string(), "quux".to_string()];
+
+    out.extend(b"Hello foo", exclusions);
+    // Check items from a previous extension are not double-counted.
+    out.extend(b"! This is a qu", exclusions);
+    // Check items are detected across extensions.
+    out.extend(b"ux.", exclusions);
+
+    match out {
+        ProcOutput::Full { excluded_len, .. } => assert_eq!(
+            excluded_len,
+            EXCLUDED_PLACEHOLDER_LEN * exclusions.len() as isize
+                - exclusions.iter().map(|i| i.len() as isize).sum::<isize>()
+        ),
+        ProcOutput::Abbreviated { .. } => panic!("out should not be abbreviated"),
+    }
+
+    assert_eq!(b"Hello foo! This is a quux.", &*out.into_bytes());
+}
+
+#[test]
+fn test_abbreviate_exclusions_avoid_abbreviations() {
+    let mut out = ProcOutput::new();
+    let exclusions = &[std::iter::repeat('a').take(64).collect::<String>()];
+
+    let mut expected = vec![b'.'; HEAD_LEN - EXCLUDED_PLACEHOLDER_LEN as usize];
+    expected.extend_from_slice(exclusions[0].as_bytes());
+    expected.extend_from_slice(&vec![b'.'; TAIL_LEN]);
+
+    out.extend(&expected, exclusions);
+
+    // We first check the length to avoid endless terminal output if the length differs, since
+    // `out` is hundreds of KBs in size.
+    let out = out.into_bytes();
+    assert_eq!(expected.len(), out.len());
+    assert_eq!(expected, out);
+}
+
+#[test]
+fn test_abbreviate_exclusions_can_still_cause_abbreviations() {
+    let mut out = ProcOutput::new();
+    let exclusions = &[std::iter::repeat('a').take(64).collect::<String>()];
+
+    let mut input = vec![b'.'; HEAD_LEN];
+    input.extend_from_slice(&vec![b'.'; TAIL_LEN]);
+    input.extend_from_slice(exclusions[0].as_bytes());
+
+    let mut expected = vec![b'.'; HEAD_LEN];
+    expected.extend_from_slice(b"\n\n<<<<<< SKIPPED 64 BYTES >>>>>>\n\n");
+    expected.extend_from_slice(&vec![b'.'; TAIL_LEN - 64]);
+    expected.extend_from_slice(&vec![b'a'; 64]);
+
+    out.extend(&input, exclusions);
+
+    // We first check the length to avoid endless terminal output if the length differs, since
+    // `out` is hundreds of KBs in size.
+    let out = out.into_bytes();
+    assert_eq!(expected.len(), out.len());
+    assert_eq!(expected, out);
+}