diff --git a/sesame2spiner/CMakeLists.txt b/sesame2spiner/CMakeLists.txt
index fd211ab86a..5eccca3ecf 100644
--- a/sesame2spiner/CMakeLists.txt
+++ b/sesame2spiner/CMakeLists.txt
@@ -12,27 +12,32 @@
 # publicly and display publicly, and to permit others to do so.
 #------------------------------------------------------------------------------
 
-add_executable(sesame2spiner
-               io_eospac.cpp
-	       io_eospac.hpp
-
-               generate_files.cpp
-	       generate_files.hpp
-
-	       parse_cli.cpp
-	       parse_cli.hpp
-
-               parser.cpp
-	       parser.hpp
-
-               main.cpp
-              )
-
-target_include_directories(sesame2spiner PUBLIC  
+add_library(sesame2spiner-lib
+  io_eospac.cpp
+  io_eospac.hpp
+  
+  generate_files.cpp
+  generate_files.hpp
+  
+  parse_cli.cpp
+  parse_cli.hpp
+  
+  parser.cpp
+  parser.hpp
+  )
+
+target_include_directories(sesame2spiner-lib PUBLIC  
                            ${CMAKE_CURRENT_BINARY_DIR}
                            ${CMAKE_CURRENT_SOURCE_DIR}
                           )
 
-target_link_libraries(sesame2spiner singularity-eos::libs singularity-eos::flags)
+target_link_libraries(sesame2spiner-lib
+  singularity-eos::libs singularity-eos::flags)
+
+add_executable(sesame2spiner
+  main.cpp
+  )
 
-# TODO: Add tests for sesame2spiner here.
+target_link_libraries(sesame2spiner
+  sesame2spiner-lib
+  singularity-eos::libs singularity-eos::flags)
diff --git a/sesame2spiner/generate_files.cpp b/sesame2spiner/generate_files.cpp
index e809472ca6..90f6eb861a 100644
--- a/sesame2spiner/generate_files.cpp
+++ b/sesame2spiner/generate_files.cpp
@@ -151,11 +151,6 @@ herr_t saveAllMaterials(const std::string &savename,
                         Verbosity eospacWarn) {
   std::vector<Params> params;
   std::vector<int> matids;
-  std::unordered_map<std::string, int> used_names;
-  std::unordered_set<int> used_matids;
-  SesameMetadata metadata;
-  hid_t file;
-  herr_t status = H5_SUCCESS;
 
   for (auto const &filename : filenames) {
     Params p(filename);
@@ -169,61 +164,7 @@ herr_t saveAllMaterials(const std::string &savename,
     params.push_back(p);
   }
 
-  std::cout << "Saving to file " << savename << std::endl;
-  file = H5Fcreate(savename.c_str(), H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
-
-  std::cout << "Processing " << matids.size() << " materials..." << std::endl;
-
-  for (size_t i = 0; i < matids.size(); i++) {
-    int matid = matids[i];
-    if (used_matids.count(matid) > 0) {
-      std::cerr << "...Duplicate matid " << matid << " detected. Skipping." << std::endl;
-      continue;
-    }
-    used_matids.insert(matid);
-
-    std::cout << "..." << matid << std::endl;
-
-    eosGetMetadata(matid, metadata, Verbosity::Debug);
-    if (printMetadata) std::cout << metadata << std::endl;
-
-    std::string name = params[i].Get("name", metadata.name);
-    if (name == "-1" || name == "") {
-      std::string new_name = "material_" + std::to_string(i);
-      std::cerr << "...WARNING: no reasonable name found. "
-                << "Using a default name: " << new_name << std::endl;
-      name = new_name;
-    }
-    if (used_names.count(name) > 0) {
-      used_names[name] += 1;
-      std::string new_name = name + "_" + std::to_string(used_names[name]);
-      std::cerr << "...WARNING: Name " << name << " already used. "
-                << "Using name: " << new_name << std::endl;
-      name = new_name;
-    } else {
-      used_names[name] = 1;
-    }
-
-    Bounds lRhoBounds, lTBounds, leBounds;
-    getMatBounds(i, matid, metadata, params[i], lRhoBounds, lTBounds, leBounds);
-
-    if (eospacWarn == Verbosity::Debug) {
-      std::cout << "bounds for log(rho), log(T), log(sie) are:\n"
-                << lRhoBounds << lTBounds << leBounds << std::endl;
-    }
-
-    status +=
-        saveMaterial(file, metadata, lRhoBounds, lTBounds, leBounds, name, eospacWarn);
-    if (status != H5_SUCCESS) {
-      std::cerr << "WARNING: problem with HDf5" << std::endl;
-    }
-  }
-
-  std::cout << "Cleaning up." << std::endl;
-  status += H5Fclose(file);
-  if (status != H5_SUCCESS) {
-    std::cerr << "WARNING: problem with HDf5" << std::endl;
-  }
+  herr_t status = saveAllMaterials(savename, matids, params, printMetadata, eospacWarn);
   return status;
 }
 
@@ -305,6 +246,74 @@ void getMatBounds(int i, int matid, const SesameMetadata &metadata, const Params
   return;
 }
 
+herr_t saveAllMaterials(const std::string &savename, const std::vector<int> matids,
+                        const std::vector<Params> &params, bool printMetadata,
+                        Verbosity eospacWarn) {
+  std::unordered_map<std::string, int> used_names;
+  std::unordered_set<int> used_matids;
+  SesameMetadata metadata;
+  hid_t file;
+  herr_t status = H5_SUCCESS;
+
+  std::cout << "Saving to file " << savename << std::endl;
+  file = H5Fcreate(savename.c_str(), H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
+
+  std::cout << "Processing " << matids.size() << " materials..." << std::endl;
+
+  for (size_t i = 0; i < matids.size(); i++) {
+    int matid = matids[i];
+    if (used_matids.count(matid) > 0) {
+      std::cerr << "...Duplicate matid " << matid << " detected. Skipping." << std::endl;
+      continue;
+    }
+    used_matids.insert(matid);
+
+    std::cout << "..." << matid << std::endl;
+
+    eosGetMetadata(matid, metadata, Verbosity::Debug);
+    if (printMetadata) std::cout << metadata << std::endl;
+
+    std::string name = params[i].Get("name", metadata.name);
+    if (name == "-1" || name == "") {
+      std::string new_name = "material_" + std::to_string(i);
+      std::cerr << "...WARNING: no reasonable name found. "
+                << "Using a default name: " << new_name << std::endl;
+      name = new_name;
+    }
+    if (used_names.count(name) > 0) {
+      used_names[name] += 1;
+      std::string new_name = name + "_" + std::to_string(used_names[name]);
+      std::cerr << "...WARNING: Name " << name << " already used. "
+                << "Using name: " << new_name << std::endl;
+      name = new_name;
+    } else {
+      used_names[name] = 1;
+    }
+
+    Bounds lRhoBounds, lTBounds, leBounds;
+    getMatBounds(i, matid, metadata, params[i], lRhoBounds, lTBounds, leBounds);
+
+    if (eospacWarn == Verbosity::Debug) {
+      std::cout << "bounds for log(rho), log(T), log(sie) are:\n"
+                << lRhoBounds << lTBounds << leBounds << std::endl;
+    }
+
+    status +=
+        saveMaterial(file, metadata, lRhoBounds, lTBounds, leBounds, name, eospacWarn);
+    if (status != H5_SUCCESS) {
+      std::cerr << "WARNING: problem with HDf5" << std::endl;
+    }
+  }
+
+  std::cout << "Cleaning up." << std::endl;
+  status += H5Fclose(file);
+  if (status != H5_SUCCESS) {
+    std::cerr << "WARNING: problem with HDf5" << std::endl;
+  }
+
+  return status;
+}
+
 bool checkValInMatBounds(int matid, const std::string &name, Real val, Real vmin,
                          Real vmax) {
   if (val < vmin || val > vmax) {
diff --git a/sesame2spiner/generate_files.hpp b/sesame2spiner/generate_files.hpp
index 5659e867dc..98aa43ee0d 100644
--- a/sesame2spiner/generate_files.hpp
+++ b/sesame2spiner/generate_files.hpp
@@ -41,6 +41,12 @@ herr_t saveAllMaterials(const std::string &savename,
                         const std::vector<std::string> &filenames, bool printMetadata,
                         Verbosity eospacWarn);
 
+herr_t saveAllMaterials(const std::string &savename,
+                        const std::vector<int> matids,
+                        const std::vector<Params> &params,
+                        bool printMetadata = false,
+                        Verbosity eospacWarn = Verbosity::Quiet);
+
 void getMatBounds(int i, int matid, const SesameMetadata &metadata, const Params &params,
                   Bounds &lRhoBounds, Bounds &lTBounds, Bounds &leBounds);
 
diff --git a/sesame2spiner/parser.hpp b/sesame2spiner/parser.hpp
index 88e507f838..d68a3e6d36 100644
--- a/sesame2spiner/parser.hpp
+++ b/sesame2spiner/parser.hpp
@@ -34,6 +34,10 @@ class Params {
   T Get(const std::string &key, T default_value) const {
     return Contains(key) ? Get<T>(key) : default_value;
   }
+  template<typename T>
+  void Add(const std::string &key, const T &val) {
+    params[key] = std::to_string(val);
+  }
 
  private:
   void Parse(std::istream &s);