Improve filter tests

Fix a bug in Pipe::check_available that must date back 15 years...

Add destructors to compression filter so unique_ptr destructor runs
without user having to include an extra header for the owned type.

3 files changed, 10 insertions, 2 deletions

diff --git a/src/lib/filters/comp_filter.cpp b/src/lib/filters/comp_filter.cpp
index 4fdc8ffc8..2563a4907 100644
--- a/src/lib/filters/comp_filter.cpp
+++ b/src/lib/filters/comp_filter.cpp
@@ -28,6 +28,8 @@ Compression_Filter::Compression_Filter(const std::string& type, size_t level, si
       }
    }
 
+Compression_Filter::~Compression_Filter() { /* for unique_ptr */ }
+
 std::string Compression_Filter::name() const
    {
    return m_comp->name();
@@ -79,6 +81,8 @@ Decompression_Filter::Decompression_Filter(const std::string& type, size_t bs) :
       }
    }
 
+Decompression_Filter::~Decompression_Filter() { /* for unique_ptr */ }
+
 std::string Decompression_Filter::name() const
    {
    return m_comp->name();
diff --git a/src/lib/filters/comp_filter.h b/src/lib/filters/comp_filter.h
index 552dc8588..64887e161 100644
--- a/src/lib/filters/comp_filter.h
+++ b/src/lib/filters/comp_filter.h
@@ -34,6 +34,8 @@ class BOTAN_DLL Compression_Filter : public Filter
       Compression_Filter(const std::string& type,
                          size_t compression_level,
                          size_t buffer_size = 4096);
+
+      ~Compression_Filter();
    private:
       std::unique_ptr<Compression_Algorithm> m_comp;
       size_t m_buffersize, m_level;
@@ -54,6 +56,8 @@ class BOTAN_DLL Decompression_Filter : public Filter
 
       Decompression_Filter(const std::string& type,
                            size_t buffer_size = 4096);
+
+      ~Decompression_Filter();
    private:
       std::unique_ptr<Decompression_Algorithm> m_comp;
       std::size_t m_buffersize;
diff --git a/src/lib/filters/pipe_rw.cpp b/src/lib/filters/pipe_rw.cpp
index 6979bd4ce..dacc91008 100644
--- a/src/lib/filters/pipe_rw.cpp
+++ b/src/lib/filters/pipe_rw.cpp
@@ -159,7 +159,7 @@ size_t Pipe::peek(uint8_t& out, size_t offset, message_id msg) const
 
 size_t Pipe::get_bytes_read() const
    {
-   return m_outputs->get_bytes_read(DEFAULT_MESSAGE);
+   return m_outputs->get_bytes_read(default_msg());
    }
 
 size_t Pipe::get_bytes_read(message_id msg) const
@@ -169,7 +169,7 @@ size_t Pipe::get_bytes_read(message_id msg) const
 
 bool Pipe::check_available(size_t n)
    {
-   return (n <= remaining(DEFAULT_MESSAGE));
+   return (n <= remaining(default_msg()));
    }
 
 bool Pipe::check_available_msg(size_t n, message_id msg)