Add a test to make sure symlinks to inputs are allowed as outputs

conformance.yaml

@@ -1059,6 +1059,19 @@
     wf.file22:
       type: File
       value: {regex: '^B$'}
+- description: |
+    Test that symlinks to input files can be used as output files
+  versions: ["draft-2", "1.0", "1.1"]
+  id: symlink_output
+  tags: ["symlinks", "behavior"]
+  inputs:
+    dir: tests/symlink_output
+    wdl: symlink_output.wdl
+    json: symlink_output.json
+  outputs:
+    wf.outfile:
+      type: File
+      value: {regex: '^A$'}
 - description: |
     Test that files with special characters in their names are supported
   versions: ["draft-2", "1.0", "1.1"]

tests/symlink_output/symlink_output.json

@@ -0,0 +1,2 @@
+{
+}

tests/symlink_output/symlink_output.wdl

@@ -0,0 +1,42 @@
+version 1.1
+
+workflow wf {
+    input {
+    }
+    call make_file
+    call forward_file {
+        input:
+            infile = make_file.outfile
+    }
+
+    output {
+        File outfile = forward_file.outfile
+    }
+}
+
+task make_file {
+    input {
+    }
+
+    command <<<
+        echo "A" >file1.txt
+    >>>
+
+    output {
+        File outfile = "file1.txt"
+    }
+}
+
+task forward_file {
+    input {
+        File infile 
+    }
+
+    command <<<
+        ln -s ~{infile} file2.txt
+    >>>
+
+    output {
+        File outfile = "file2.txt"
+    }
+}