tests: add heredoc test

Signed-off-by: Aditya R <arajan@redhat.com>

tests/bud.bats

@@ -267,6 +267,18 @@ _EOF
   run_buildah 1 run myctr ls -l subdir/
 }
 
+@test "bud build with heredoc content" {
+  run_buildah build -t heredoc $WITH_POLICY_JSON -f $BUDFILES/heredoc/Containerfile .
+  expect_output --substring "print first line from heredoc"
+  expect_output --substring "print second line from heredoc"
+  expect_output --substring "Heredoc writing first file"
+  expect_output --substring "some text of first file"
+  expect_output --substring "file2 from python"
+  expect_output --substring "(your index page goes here)"
+  expect_output --substring "(robots content)"
+  expect_output --substring "(humans content)"
+}
+
 @test "bud with .containerignore" {
   _prefetch alpine busybox
   run_buildah 125 build -t testbud $WITH_POLICY_JSON -f $BUDFILES/containerignore/Dockerfile $BUDFILES/containerignore

tests/bud/heredoc/Containerfile

@@ -0,0 +1,35 @@
+FROM docker.io/library/python:latest
+
+RUN <<EOF
+echo "print first line from heredoc"
+echo "print second line from heredoc"
+EOF
+
+RUN <<EOF
+echo "Heredoc writing first file" >> /file1
+echo "some text of first file" >> /file1
+EOF
+
+RUN cat file1
+
+RUN python3 <<EOF
+with open("/file2", "w") as f:
+    print("file2 from python", file=f)
+EOF
+
+RUN cat file2
+
+ADD <<EOF /index.html
+ (your index page goes here)
+EOF
+
+RUN cat index.html
+
+COPY <<robots.txt <<humans.txt /test/
+(robots content)
+robots.txt
+(humans content)
+humans.txt
+
+RUN cat /test/robots.txt
+RUN cat /test/humans.txt