diff --git a/ci/affects-files.sh b/ci/affects-files.sh
new file mode 100755
index 0000000000..6657266768
--- /dev/null
+++ b/ci/affects-files.sh
@@ -0,0 +1,30 @@
+#!/usr/bin/env bash
+#
+# Checks if a CI build affects one or more path patterns.  Each command-line
+# argument is checked in series.
+#
+# Bash regular expresses are permitted in the pattern, and the colon (':')
+# character is guaranteed to appear before and after each affected file (and thus
+# can be used as an anchor), eg:
+#     .rs:    -- any file or directory ending in .rs
+#     .rs     -- also matches foo.rs.bar
+#     :snap/  -- anything under the snap/ subdirectory
+#     snap/   -- also matches foo/snap/
+#
+
+if ci/is-pr.sh; then
+  affectedFiles="$(buildkite-agent meta-data get affected_files)"
+  echo "Affected files in this PR: $affectedFiles"
+
+  for pattern in "$@"; do
+    if [[ ":$affectedFiles:" =~ $pattern ]]; then
+      exit 0
+    fi
+  done
+
+  exit 1
+fi
+
+# affected_files metadata is not currently available for non-PR builds, so assume
+# the worse (affected)
+exit 0
diff --git a/ci/buildkite.yml b/ci/buildkite.yml
index 9f49916848..1b9986c9a4 100644
--- a/ci/buildkite.yml
+++ b/ci/buildkite.yml
@@ -29,6 +29,7 @@ steps:
   - command: "ci/pr-snap.sh"
     timeout_in_minutes: 20
     name: "snap"
+    branches: "pull/*"
   - wait
   - trigger: "solana-secondary"
     branches: "!pull/*"
diff --git a/ci/pr-snap.sh b/ci/pr-snap.sh
index 116c8ed9fd..41aff8acdf 100755
--- a/ci/pr-snap.sh
+++ b/ci/pr-snap.sh
@@ -4,16 +4,11 @@ set -e
 # Only run snap.sh for pull requests that modify files under /snap
 #
 
-cd "$(dirname "$0")"
+cd "$(dirname "$0")"/..
 
-if ./is-pr.sh; then
-  affected_files="$(buildkite-agent meta-data get affected_files)"
-  echo "Affected files in this PR: $affected_files"
-  if [[ ! ":$affected_files:" =~ :snap/ ]]; then
-    echo "Skipping snap build as no files under /snap were modified"
-    exit 0
-  fi
-  exec ./snap.sh
-else
-  echo "Skipping snap build as this is not a pull request"
-fi
+ci/affects-files.sh :snap/ || {
+  echo "Skipping snap build as no files under /snap were modified"
+  exit 0
+}
+
+exec ci/snap.sh
diff --git a/ci/test-coverage.sh b/ci/test-coverage.sh
index b3cf53868d..7545dc41a2 100755
--- a/ci/test-coverage.sh
+++ b/ci/test-coverage.sh
@@ -9,15 +9,15 @@ annotate() {
   }
 }
 
-if ci/is-pr.sh; then
-  affectedFiles="$(buildkite-agent meta-data get affected_files)"
-  echo "Affected files in this PR: $affectedFiles"
-  if [[ ! ":$affectedFiles:" =~ \.rs: ]]; then
-    annotate --style info --context coverage-info \
-      "Coverage skipped as no .rs files were modified"
-    exit 0
-  fi
-fi
+ci/affects-files.sh \
+  .rs: \
+  ci/test-coverage.sh: \
+  scripts/coverage.sh: \
+|| {
+  annotate --style info --context coverage-info \
+    "Coverage skipped as no .rs files were modified"
+  exit 0
+}
 
 source ci/upload-ci-artifact.sh
 ci/version-check-with-upgrade.sh nightly