diff --git a/bopytex/message.py b/bopytex/message.py
new file mode 100644
index 0000000..bdfb69c
--- /dev/null
+++ b/bopytex/message.py
@@ -0,0 +1,33 @@
+class Message():
+    def __init__(self, status, out, err):
+        self._status = status
+        self._out = out
+        self._err = err
+
+    @property
+    def status(self):
+        return self._status
+
+    @property
+    def out(self):
+        return self._out
+
+    @property
+    def err(self):
+        return self._err
+
+class SubprocessMessage(Message):
+    def __init__(self, process):
+        self._process = process
+
+    @property
+    def status(self):
+        return self._process.wait()
+
+    @property
+    def out(self):
+        return self._process.stdout
+
+    @property
+    def err(self):
+        return self._process.stderr
diff --git a/bopytex/worker/compile.py b/bopytex/worker/compile.py
index 24a9531..256c0f5 100644
--- a/bopytex/worker/compile.py
+++ b/bopytex/worker/compile.py
@@ -1,4 +1,5 @@
 import subprocess
+from ..message import SubprocessMessage
 
 
 def latexmk(args: dict, deps, output):
@@ -8,5 +9,5 @@ def latexmk(args: dict, deps, output):
         stderr=subprocess.PIPE,
         universal_newlines=True
     )
-    yield from compile_process.stderr
+    return SubprocessMessage(compile_process)
 
diff --git a/bopytex/worker/generate.py b/bopytex/worker/generate.py
index ff80f76..b6a9cf3 100644
--- a/bopytex/worker/generate.py
+++ b/bopytex/worker/generate.py
@@ -1,12 +1,20 @@
 from jinja2.environment import Template
 
+from bopytex.message import Message
+
 
 def generate(args, deps, output):
     env = args["jinja2"]["environment"]
     template = env.get_template(deps[0])
-    with open(output, "w") as out:
-        out.write(tpl2tex(template, metas=args))
-    yield f"GENERATE - {deps[0]} to {output}"
+
+    try:
+        with open(output, "w") as out:
+            out.write(tpl2tex(template, metas=args))
+
+        return Message(0, [f"GENERATE - {deps[0]} to {output}"], [])
+
+    except Exception as e:
+        return Message(0, [], [e])
 
 
 def tpl2tex(template: Template, metas: dict = {}) -> str:
diff --git a/bopytex/worker/join_pdf.py b/bopytex/worker/join_pdf.py
index 45927f1..2a44f04 100644
--- a/bopytex/worker/join_pdf.py
+++ b/bopytex/worker/join_pdf.py
@@ -1,5 +1,7 @@
 import subprocess
 
+from bopytex.message import SubprocessMessage
+
 def pdfjam(args: dict, deps, output):
     joining_process = subprocess.Popen(
         ["pdfjam"] +  deps + ["-o", output],
@@ -7,11 +9,5 @@ def pdfjam(args: dict, deps, output):
         stderr=subprocess.PIPE,
         universal_newlines=True,
     )
-    # exit_code is always 66...
-    exit_code = joining_process.wait()
-
-    if  exit_code == 0:
-        yield "pdfjam success"
-    else:
-        yield "pdfjam failed"
+    return SubprocessMessage(joining_process)
 
diff --git a/test/worker/test_compile.py b/test/worker/test_compile.py
index 7e1c96e..edd2fc3 100644
--- a/test/worker/test_compile.py
+++ b/test/worker/test_compile.py
@@ -22,14 +22,14 @@ extra parameters or packages included.
     return source
 
 
-def test_compile(tex_path):
+def test_latexmk(tex_path):
     tmp_path = tex_path.parent
     os.chdir(tmp_path)
 
     texfile = str(tex_path.name)
     output = "source.pdf"
 
-    for err in latexmk({}, [texfile], "source.pdf"):
-        assert 0
+    message = latexmk({}, [texfile], "source.pdf")
 
+    assert message.status == 0
     assert Path(output).exists
diff --git a/test/worker/test_generate.py b/test/worker/test_generate.py
index ab90ba7..fbd3baf 100644
--- a/test/worker/test_generate.py
+++ b/test/worker/test_generate.py
@@ -34,12 +34,15 @@ def test_generate(template_path, jinja2_env):
     template = str(template_path.name)
     output = "output"
 
-    result = next(generate(
+    message = generate(
         args={"a": 2, "jinja2": {"environment": jinja2_env}},
         deps=[template],
         output=output,
-    ))
-    assert result == "GENERATE - template.j2 to output"
+    )
+    print(message.err)
+    assert message.status == 0
+    assert message.out == ["GENERATE - template.j2 to output"]
+
     with open(output, "r") as out:
         lines = out.readlines()
         assert lines == ["Plop 2"]
diff --git a/test/worker/test_join_pdf.py b/test/worker/test_join_pdf.py
index 5edd7a4..26ae726 100644
--- a/test/worker/test_join_pdf.py
+++ b/test/worker/test_join_pdf.py
@@ -31,9 +31,9 @@ def test_join_pdf(multiple_pdf):
 
     output = "joined.pdf"
 
-    for msg in pdfjam({"pwd": Path.cwd()}, deps, output):
-        assert msg == "pdfjam success"
+    message = pdfjam({"pwd": Path.cwd()}, deps, output)
 
+    assert message.status == 0
     assert Path(output).exists()
 
 
@@ -45,7 +45,7 @@ def test_join_pdf_failed(multiple_pdf):
 
     output = "joined.pdf"
 
-    for msg in pdfjam({"pwd": Path.cwd()}, deps, output):
-        assert msg == "pdfjam failed"
+    message = pdfjam({"pwd": Path.cwd()}, deps, output)
 
+    assert message.status == 66
     assert not Path(output).exists()