net_err_suggests_fetch_with_cli: fix false positives

Some test systems have catch-all DNS resolvers that point
needs-proxy.invalid to loopback, resulting in a connection refused OS
error instead the expected Net error. This change uses a known invalid
IP to bypass any potential DNS, and also adds an extremely short timeout
to enforce a Net error.

Also make the test pattern matching a bit more fuzzy to avoid future
false positives.

Remove the standalone Cargo.toml file and integrate it into the main
script to be able to parametrize it.

tests/Sanity/net_err_suggests_fetch_with_cli/Cargo.toml

@@ -1,8 +0,0 @@
-[package]
-name = "foo"
-version = "0.0.0"
-edition = "2015"
-authors = []
-
-[dependencies]
-foo = { git = "https://needs-proxy.invalid/git" }

tests/Sanity/net_err_suggests_fetch_with_cli/runtest.sh

@@ -2,6 +2,34 @@
 # vim: dict+=/usr/share/beakerlib/dictionary.vim cpt=.,w,b,u,t,i,k
 . /usr/share/beakerlib/beakerlib.sh || exit 1
 
+# For the test remote depenency, we use a TEST-NET-1 address (192.0.2.1) instead
+# "needs-proxy.invalid" like upstream, to deal with potential catch-all DNS
+# resolvers that redirect any invalid domain to loopback. These result in a
+# connection refused (OS error) for any invalid host, but we need a network
+# error for cargo to recommend using fetch-with-cli.SS
+# To achieve it we use a documented test IP with a very short timeout that
+# will simulate the same effect of unreachable host, causing cargo to suggest
+# using the git fetch option.
+
+CRATE_NAME="foo"
+CRATE_VER="0.0.0"
+REMOTE_URL="https://192.0.2.1/git"
+
+
+function generate_cargo_toml() {
+    local dest_dir=$1
+    cat >> "$dest_dir/Cargo.toml" <<EOF
+[package]
+name = "$CRATE_NAME"
+version = "$CRATE_VER"
+edition = "2015"
+authors = []
+
+[dependencies]
+foo = { git = "$REMOTE_URL" }
+EOF
+}
+
 function generate_cargo_conffile() {
     mkdir ".cargo"
     cat >> .cargo/config.toml <<EOF
@@ -15,8 +43,8 @@ function test_git-fetch-with-cli() {
     local log_file
     log_file=$(mktemp)
 
-    rlRun "$cargo_cmd 2> $log_file" 101
-    rlAssertGrep 'Unable to update https://needs-proxy.invalid/git' "$log_file" || cat "$log_file"
+    rlRun "$cargo_cmd |& tee $log_file" 101
+    rlAssertGrep "Unable to update $REMOTE_URL" "$log_file" || cat "$log_file"
     rlAssertNotGrep "net.git-fetch-with-cli" "$log_file" || cat "$log_file"
 
     rm -f "$log_file"
@@ -26,18 +54,22 @@ rlJournalStart
     rlPhaseStartSetup
         declare tmp
         rlRun "tmp=\$(mktemp -d)" 0 "Create tmp directory"
-        rlRun "cp Cargo.toml $tmp"
+        # rlRun "cp Cargo.toml $tmp"
+        rlRun "generate_cargo_toml $tmp"
         rlRun "pushd $tmp"
         rlRun "mkdir src && touch src/lib.rs"
         rlRun "set -o pipefail"
-
+        # Cargo will try to resolve an IP that will never reply back.
+        # To make the test run faster, reduce the timeout to 1 second instead
+        # the default 30s
+        rlRun "export HTTP_TIMEOUT=1"
     rlPhaseEnd
 
     rlPhaseStartTest
-        rlRun "cargo check -v 2> output.log" 101
+        rlRun "cargo check -v |& tee output.log" 101
         # Ensure DNS was not able to resolve the remote
-        rlAssertGrep 'spurious network error \([0-9]+ .* remaining\): .*resolve .*needs-proxy\.invalid: .*known' output.log -E
-        rlAssertGrep 'Unable to update https://needs-proxy.invalid/git' output.log
+        rlAssertGrep 'spurious network error' output.log
+        rlAssertGrep "Unable to update $REMOTE_URL" output.log
         # Ensure cargo suggests using net.git-fetch-with-cli
         rlAssertGrep "net.git-fetch-with-cli" output.log