diff --git a/.editorconfig b/.editorconfig
new file mode 100644
index 0000000..a2eb55d
--- /dev/null
+++ b/.editorconfig
@@ -0,0 +1,5 @@
+root = true
+
+[*.{c,h}]
+indent_style = space
+indent_size = 2
diff --git a/Makefile b/Makefile
index fadf89d..78f6a1c 100644
--- a/Makefile
+++ b/Makefile
@@ -11,7 +11,8 @@ INC_DIRS ?= include
 LIB := $(BUILD_DIR)/$(LIB_FILENAME)
 
 SRCS != find '$(SRC_DIR)' -iname '*.c'
-SRCS_H != find $(INC_DIRS) '$(SRC_DIR)' -iname '*.h'
+SRCS_H != find $(INC_DIRS) -iname '*.h'
+SRCS_H_INTERNAL != find $(SRC_DIR) -iname '*.h'
 SRCS_TEST != find '$(TEST_DIR)' -iname '*.c'
 
 OBJS := $(SRCS:%=$(BUILD_DIR)/%.o)
@@ -86,16 +87,22 @@ $(BUILD_DIR)/$(TEST_DIR)/%.c.o: $(TEST_DIR)/%.c
 # =====MAINTENANCE=====
 .PHONY: lint
 lint:
-	clang-format -n --Werror $(SRCS) $(SRCS_H)
+	clang-format -n --Werror $(SRCS) $(SRCS_H) $(SRCS_H_INTERNAL)
 
 .PHONY: fmt
 fmt:
-	clang-format -i $(SRCS) $(SRCS_H)
+	clang-format -i $(SRCS) $(SRCS_H) $(SRCS_H_INTERNAL)
 
 .PHONY: clean
 clean:
 	rm -rf $(BUILD_DIR)
 
 
+.PHONY: bear
+bear: clean
+	bear -- make
+	bear --append -- make build-test
+
+
 # Make make aware of the .d files
 -include $(DEPS)
diff --git a/include/vieter_cat_heap.h b/include/vieter_cat_heap.h
new file mode 100644
index 0000000..f25df00
--- /dev/null
+++ b/include/vieter_cat_heap.h
@@ -0,0 +1,30 @@
+#ifndef VIETER_CAT_HEAP
+#define VIETER_CAT_HEAP
+
+#include <stdint.h>
+
+typedef struct vieter_cat_heap vieter_cat_heap;
+
+typedef enum vieter_cat_heap_error {
+  vieter_cat_heap_ok = 0,
+  vieter_cat_heap_arch_empty = 1,
+  vieter_cat_heap_arch_not_found = 2
+} vieter_cat_heap_error;
+
+vieter_cat_heap *vieter_cat_heap_init();
+
+void vieter_cat_heap_free(vieter_cat_heap *cheap);
+
+uint64_t vieter_cat_heap_size(vieter_cat_heap *cheap);
+
+vieter_cat_heap_error vieter_cat_heap_insert(vieter_cat_heap *cheap,
+                                             char *category, uint64_t key,
+                                             void *data);
+
+vieter_cat_heap_error vieter_cat_heap_pop(void **out, vieter_cat_heap *cheap,
+                                          char *category);
+
+vieter_cat_heap_error vieter_cat_heap_peek(void **out, vieter_cat_heap *cheap,
+                                           char *category);
+
+#endif
diff --git a/include/vieter_job_queue.h b/include/vieter_job_queue.h
new file mode 100644
index 0000000..cded82f
--- /dev/null
+++ b/include/vieter_job_queue.h
@@ -0,0 +1,160 @@
+#ifndef VIETER_JOB_QUEUE
+#define VIETER_JOB_QUEUE
+
+#include "vieter_cron.h"
+#include <stdbool.h>
+#include <stdint.h>
+
+/*
+ * The order of these do not imply that they happen in this order. New states
+ * will just get added as consecutive numbers. Their values should be
+ * monotonically increasing values, as these will be used to index arrays, among
+ * other things.
+ */
+typedef enum vieter_job_state {
+  vieter_job_state_queued = 0,
+  vieter_job_state_ready = 1,
+  vieter_job_state_build_finished = 2,
+  vieter_job_state_failed = 3
+} vieter_job_state;
+
+// This macro should be kept in sync with the above enum
+#define VIETER_JOB_STATES 4
+// Neither of these states are allowed to be categorized
+#define VIETER_JOB_INITIAL_STATE vieter_job_state_queued
+#define VIETER_JOB_FAILURE_STATE vieter_job_state_failed
+// Bitmap describing what states should be divided into multiple architectures
+#define VIETER_JOB_STATES_ARCH 0b0010
+#define VIETER_JOB_STATE_IS_ARCH(i) (VIETER_JOB_STATES_ARCH & (1 << i))
+
+/*
+ * Struct storing a report for why a certain job failed to be processed in the
+ * given state.
+ */
+typedef struct vieter_job_failure_report {
+  vieter_job_state failed_state;
+  char *msg;
+} vieter_job_failure_report;
+
+vieter_job_failure_report *vieter_job_failure_report_init();
+
+void vieter_job_failure_report_free(vieter_job_failure_report *report);
+
+/*
+ * Represents a job currently being processed in the system. A job migrates
+ * between different states before finally being removed from the queue.
+ */
+typedef struct vieter_job {
+  uint64_t id;
+  uint64_t next_scheduled_time;
+  vieter_cron_expression *schedule;
+  void *build_config;
+  char *arch;
+  vieter_job_failure_report *failure_report;
+  uint64_t state_transition_times[VIETER_JOB_STATES];
+  vieter_job_state current_state;
+  bool single;
+  bool dispatched;
+} vieter_job;
+
+/*
+ * Allocate a new vieter_job object.
+ */
+vieter_job *vieter_job_init();
+
+void vieter_job_free(vieter_job *job);
+
+/*
+ * Represents the actual queue managing the list of jobs.
+ */
+typedef struct vieter_job_queue vieter_job_queue;
+
+typedef enum vieter_job_queue_error {
+  vieter_job_queue_ok = 0,
+  vieter_job_queue_not_present = 1,
+  vieter_job_queue_already_present = 2,
+  vieter_job_queue_state_empty = 3,
+  vieter_job_queue_not_dispatched = 4,
+  vieter_job_queue_state_is_arch = 5,
+  vieter_job_queue_state_is_not_arch = 6,
+} vieter_job_queue_error;
+
+/*
+ * Allocate and initialize a new job queue.
+ */
+vieter_job_queue *vieter_job_queue_init();
+
+/*
+ * Free a job queue.
+ */
+void vieter_job_queue_free(vieter_job_queue *queue);
+
+/*
+ * Insert the given job into the system.
+ */
+vieter_job_queue_error vieter_job_queue_insert(vieter_job_queue *queue,
+                                               vieter_job *job);
+
+/*
+ * Pop a job from the given non-categorized state's queue. The job will then be
+ * marked as dispatched.
+ */
+vieter_job_queue_error vieter_job_queue_pop(vieter_job **out,
+                                            vieter_job_queue *queue,
+                                            vieter_job_state state);
+
+/*
+ * Pop a job from the given categorized state's queue. The job will then be
+ * marked as dispatched.
+ */
+vieter_job_queue_error vieter_job_queue_pop_arch(vieter_job **out,
+                                                 vieter_job_queue *queue,
+                                                 vieter_job_state state,
+                                                 char *arch);
+
+/*
+ * Transition the job with the given id to the new state. This sets the
+ * job's dispatch flag to false, and adds it to the new state's queue.
+ *
+ * NOTE: this can only be done with dispatched jobs.
+ */
+vieter_job_queue_error vieter_job_queue_transition(vieter_job_queue *queue,
+                                                   uint64_t id,
+                                                   vieter_job_state new_state);
+
+/*
+ * Remove the given job from the job queue, returning its pointer to the caller.
+ *
+ * NOTE: this can only be done with dispatched jobs.
+ */
+vieter_job_queue_error
+vieter_job_queue_remove(vieter_job **out, vieter_job_queue *queue, uint64_t id);
+
+/*
+ * Transition a job into the failure state, and attach a failure report with the
+ * provided message. The message is copied, so the caller is responsible for
+ * freeing the provided string.
+ *
+ * NOTE: this can only be done with dispatched jobs.
+ */
+vieter_job_queue_error vieter_job_queue_fail(vieter_job_queue *queue,
+                                             uint64_t id, char *report_message);
+/*
+ * Acquire a read lock on the job queue. Return value is the result of
+ * pthread_rwlock_rdlock.
+ */
+int vieter_job_queue_rlock(vieter_job_queue *job_queue);
+
+/*
+ * Acquire a write lock on the job queue. Return value is the result of
+ * pthread_rwlock_wrlock.
+ */
+int vieter_job_queue_wlock(vieter_job_queue *job_queue);
+
+/*
+ * Unlock the lock after having acquired it. Return value is the result of
+ * pthread_rwlock_unlock.
+ */
+int vieter_job_queue_unlock(vieter_job_queue *job_queue);
+
+#endif
diff --git a/include/vieter_tree.h b/include/vieter_tree.h
index 2079eb9..4da500f 100644
--- a/include/vieter_tree.h
+++ b/include/vieter_tree.h
@@ -67,4 +67,22 @@ void vieter_tree_iterator_free(vieter_tree_iterator **ptp);
 vieter_tree_error vieter_tree_iterator_next(void **out,
                                             vieter_tree_iterator *iter);
 
+/*
+ * Acquire a read lock on the tree. Return value is the result of
+ * pthread_rwlock_rdlock.
+ */
+int vieter_tree_rlock(vieter_tree *tree);
+
+/*
+ * Acquire a write lock on the tree. Return value is the result of
+ * pthread_rwlock_wrlock.
+ */
+int vieter_tree_wlock(vieter_tree *tree);
+
+/*
+ * Unlock the lock after having acquired it. Return value is the result of
+ * pthread_rwlock_unlock.
+ */
+int vieter_tree_unlock(vieter_tree *tree);
+
 #endif
diff --git a/src/cat-heap/README.md b/src/cat-heap/README.md
new file mode 100644
index 0000000..bbdfa0b
--- /dev/null
+++ b/src/cat-heap/README.md
@@ -0,0 +1,4 @@
+A category heap consists of a collection of heaps, with each heap representing
+a certain category. In practice, this category would be an architecture (e.g.
+`x86_64`). This is used by the job queue to have a queue for each architecture
+for a given state.
diff --git a/src/cat-heap/vieter_cat_heap.c b/src/cat-heap/vieter_cat_heap.c
new file mode 100644
index 0000000..d0a00a0
--- /dev/null
+++ b/src/cat-heap/vieter_cat_heap.c
@@ -0,0 +1,104 @@
+#include "vieter_cat_heap_internal.h"
+
+vieter_cat_heap *vieter_cat_heap_init() {
+  return calloc(1, sizeof(vieter_cat_heap));
+}
+
+void vieter_cat_heap_free(vieter_cat_heap *cheap) {
+  if (cheap->cat_count > 0) {
+    for (uint64_t i = 0; i < cheap->cat_count; i++) {
+      free(cheap->categories[i]);
+      vieter_heap_free(cheap->heaps[i]);
+    }
+
+    free(cheap->categories);
+    free(cheap->heaps);
+  }
+
+  free(cheap);
+}
+
+uint64_t vieter_cat_heap_size(vieter_cat_heap *cheap) {
+  uint64_t total = 0;
+
+  for (uint64_t i = 0; i < cheap->cat_count; i++) {
+    total += vieter_heap_size(cheap->heaps[i]);
+  }
+
+  return total;
+}
+
+vieter_cat_heap_error vieter_cat_heap_insert(vieter_cat_heap *cheap,
+                                             char *category, uint64_t key,
+                                             void *data) {
+  uint64_t i = 0;
+
+  // For now, we do a linear search through all categories. This is more than
+  // fast enough for most usecases.
+  while (i < cheap->cat_count && strcmp(category, cheap->categories[i]) != 0) {
+    i++;
+  }
+
+  if (i == cheap->cat_count) {
+    if (cheap->cat_count == 0) {
+      cheap->categories = malloc(sizeof(char *));
+      cheap->heaps = malloc(sizeof(vieter_heap *));
+    } else {
+      cheap->categories =
+          realloc(cheap->categories, sizeof(char *) * (cheap->cat_count + 1));
+      cheap->heaps =
+          realloc(cheap->heaps, sizeof(vieter_heap *) * (cheap->cat_count + 1));
+    }
+
+    cheap->cat_count++;
+
+    cheap->categories[i] = strdup(category);
+    cheap->heaps[i] = vieter_heap_init();
+  }
+
+  vieter_heap_insert(cheap->heaps[i], key, data);
+
+  return vieter_cat_heap_ok;
+}
+
+vieter_cat_heap_error vieter_cat_heap_pop(void **out, vieter_cat_heap *cheap,
+                                          char *category) {
+  uint64_t i = 0;
+
+  while (i < cheap->cat_count && strcmp(category, cheap->categories[i]) != 0) {
+    i++;
+  }
+
+  if (i == cheap->cat_count) {
+    return vieter_cat_heap_arch_not_found;
+  }
+
+  vieter_heap_error res = vieter_heap_pop(out, cheap->heaps[i]);
+
+  if (res != vieter_heap_ok) {
+    return vieter_cat_heap_arch_empty;
+  }
+
+  return vieter_cat_heap_ok;
+}
+
+vieter_cat_heap_error vieter_cat_heap_peek(void **out, vieter_cat_heap *cheap,
+                                           char *category) {
+  uint64_t i = 0;
+
+  while (i < cheap->cat_count && strcmp(category, cheap->categories[i]) != 0) {
+    i++;
+  }
+
+  if (i == cheap->cat_count) {
+    return vieter_cat_heap_arch_not_found;
+  }
+
+  vieter_heap_error res = vieter_heap_peek(out, cheap->heaps[i]);
+
+  if (res != vieter_heap_ok) {
+    return vieter_cat_heap_arch_empty;
+  }
+
+  return vieter_cat_heap_ok;
+}
diff --git a/src/cat-heap/vieter_cat_heap_internal.h b/src/cat-heap/vieter_cat_heap_internal.h
new file mode 100644
index 0000000..a4a3f2c
--- /dev/null
+++ b/src/cat-heap/vieter_cat_heap_internal.h
@@ -0,0 +1,10 @@
+#include "vieter_cat_heap.h"
+#include "vieter_heap.h"
+#include <stdlib.h>
+#include <string.h>
+
+struct vieter_cat_heap {
+  uint64_t cat_count;
+  char **categories;
+  vieter_heap **heaps;
+};
diff --git a/src/job-queue/README.md b/src/job-queue/README.md
new file mode 100644
index 0000000..8fa9c94
--- /dev/null
+++ b/src/job-queue/README.md
@@ -0,0 +1,27 @@
+The goal of this job queue design is to process jobs in order, with each job
+moving through a pipeline of tasks that need to be completed.
+
+At any given time, a job is in one of a few given states, e.g. "queued". These
+states are explained below. Along with this, each job also has a "dispatched"
+flag. If this flag is set to true, it means this job is currently being
+processed. "Being processed" could mean anything; it depends entirely on the
+state a job's in. While a job is dispatched, it is no longer present in the
+priority queue of its respective state.
+
+## Job
+
+A job describes a scheduled build as it moves through the pipeline of states.
+The job queue datastructure keeps track of all jobs in a central red-black
+binary tree. For each state, a priority queue tracks in what order jobs should
+be processed.
+
+## States
+
+* `queued`: a job that's in the job queue but does not yet need to be executed
+  (as defined by its timestamp)
+* `ready`: a job that's scheduled for building, with all preprocessing tasks
+  fulfilled.
+* `build_finished`: a job whose build has finished, and is waiting for any
+  post-build tasks.
+* `failed`: a job whose processing failed at some point. Jobs in this state
+  include a failure report that describes in what state they failed, and why.
diff --git a/src/job-queue/vieter_job.c b/src/job-queue/vieter_job.c
new file mode 100644
index 0000000..15633c1
--- /dev/null
+++ b/src/job-queue/vieter_job.c
@@ -0,0 +1,24 @@
+#include "vieter_job_queue_internal.h"
+
+vieter_job *vieter_job_init() { return calloc(1, sizeof(vieter_job)); }
+
+void vieter_job_free(vieter_job *job) {
+  if (job->schedule != NULL) {
+    vieter_cron_expr_free(job->schedule);
+  }
+
+  if (job->failure_report != NULL) {
+    vieter_job_failure_report_free(job->failure_report);
+  }
+
+  free(job);
+}
+
+vieter_job_failure_report *vieter_job_failure_report_init() {
+  return calloc(1, sizeof(vieter_job_failure_report));
+}
+
+void vieter_job_failure_report_free(vieter_job_failure_report *report) {
+  free(report->msg);
+  free(report);
+}
diff --git a/src/job-queue/vieter_job_queue.c b/src/job-queue/vieter_job_queue.c
new file mode 100644
index 0000000..028b1af
--- /dev/null
+++ b/src/job-queue/vieter_job_queue.c
@@ -0,0 +1,183 @@
+#include "vieter_job_queue_internal.h"
+
+vieter_job_queue *vieter_job_queue_init() {
+  vieter_job_queue *queue = malloc(sizeof(vieter_job_queue));
+
+  queue->tree = vieter_tree_init();
+
+  for (int i = 0; i < VIETER_JOB_STATES; i++) {
+    if (VIETER_JOB_STATE_IS_ARCH(i)) {
+      queue->heaps[i].cat_heap = vieter_cat_heap_init();
+    } else {
+      queue->heaps[i].heap = vieter_heap_init();
+    }
+  }
+
+  return queue;
+}
+
+void vieter_job_queue_free(vieter_job_queue *queue) {
+  vieter_tree_free(queue->tree);
+
+  for (int i = 0; i < VIETER_JOB_STATES; i++) {
+    if (VIETER_JOB_STATE_IS_ARCH(i)) {
+      vieter_cat_heap_free(queue->heaps[i].cat_heap);
+    } else {
+      vieter_heap_free(queue->heaps[i].heap);
+    }
+  }
+
+  free(queue);
+}
+
+vieter_job_queue_error vieter_job_queue_insert(vieter_job_queue *queue,
+                                               vieter_job *job) {
+  vieter_tree_error tree_res = vieter_tree_insert(queue->tree, job->id, job);
+
+  if (tree_res != vieter_tree_ok) {
+    return vieter_job_queue_already_present;
+  }
+
+  // We assume that the initial state is not a category heap
+  vieter_heap_insert(queue->heaps[VIETER_JOB_INITIAL_STATE].heap,
+                     job->next_scheduled_time, job);
+
+  job->current_state = VIETER_JOB_INITIAL_STATE;
+  job->dispatched = false;
+  job->state_transition_times[VIETER_JOB_INITIAL_STATE] = time(NULL);
+
+  return vieter_job_queue_ok;
+}
+
+vieter_job_queue_error vieter_job_queue_pop(vieter_job **out,
+                                            vieter_job_queue *queue,
+                                            vieter_job_state state) {
+  if (VIETER_JOB_STATE_IS_ARCH(state)) {
+    return vieter_job_queue_state_is_arch;
+  }
+
+  vieter_heap_error res =
+      vieter_heap_pop((void **)out, queue->heaps[state].heap);
+
+  if (res != vieter_heap_ok) {
+    return vieter_job_queue_state_empty;
+  }
+
+  (*out)->dispatched = true;
+
+  return vieter_job_queue_ok;
+}
+
+vieter_job_queue_error vieter_job_queue_pop_arch(vieter_job **out,
+                                                 vieter_job_queue *queue,
+                                                 vieter_job_state state,
+                                                 char *arch) {
+  if (!VIETER_JOB_STATE_IS_ARCH(state)) {
+    return vieter_job_queue_state_is_not_arch;
+  }
+
+  vieter_cat_heap_error res =
+      vieter_cat_heap_pop((void **)out, queue->heaps[state].cat_heap, arch);
+
+  if (res != vieter_cat_heap_ok) {
+    return vieter_job_queue_state_empty;
+  }
+
+  (*out)->dispatched = true;
+
+  return vieter_job_queue_ok;
+}
+
+vieter_job_queue_error vieter_job_queue_transition(vieter_job_queue *queue,
+                                                   uint64_t id,
+                                                   vieter_job_state new_state) {
+  vieter_job *job;
+
+  vieter_tree_error res = vieter_tree_search((void **)&job, queue->tree, id);
+
+  if (res != vieter_tree_ok) {
+    return vieter_job_queue_not_present;
+  }
+
+  if (!job->dispatched) {
+    return vieter_job_queue_not_dispatched;
+  }
+
+  if (VIETER_JOB_STATE_IS_ARCH(new_state)) {
+    vieter_cat_heap_insert(queue->heaps[new_state].cat_heap, job->arch,
+                           job->next_scheduled_time, job);
+  } else {
+    vieter_heap_insert(queue->heaps[new_state].heap, job->next_scheduled_time,
+                       job);
+  }
+
+  job->current_state = new_state;
+  job->dispatched = false;
+  job->state_transition_times[new_state] = time(NULL);
+
+  return vieter_job_queue_ok;
+}
+
+vieter_job_queue_error vieter_job_queue_remove(vieter_job **out,
+                                               vieter_job_queue *queue,
+                                               uint64_t id) {
+  vieter_tree_error res = vieter_tree_search((void **)out, queue->tree, id);
+
+  if (res != vieter_tree_ok) {
+    return vieter_job_queue_not_present;
+  }
+
+  vieter_job *job = *out;
+
+  if (!job->dispatched) {
+    return vieter_job_queue_not_dispatched;
+  }
+
+  // This can't fail if the search succeeded
+  vieter_tree_remove((void **)out, queue->tree, job->id);
+
+  return vieter_job_queue_ok;
+}
+
+vieter_job_queue_error vieter_job_queue_fail(vieter_job_queue *queue,
+                                             uint64_t id,
+                                             char *report_message) {
+  vieter_job *job;
+
+  vieter_tree_error res = vieter_tree_search((void **)&job, queue->tree, id);
+
+  if (res != vieter_tree_ok) {
+    return vieter_job_queue_not_present;
+  }
+
+  if (!job->dispatched) {
+    return vieter_job_queue_not_dispatched;
+  }
+
+  // We assume the failure state is not categorized
+  vieter_heap_insert(queue->heaps[VIETER_JOB_FAILURE_STATE].heap,
+                     job->next_scheduled_time, job);
+
+  job->dispatched = false;
+  job->state_transition_times[VIETER_JOB_FAILURE_STATE] = time(NULL);
+
+  job->failure_report = vieter_job_failure_report_init();
+  job->failure_report->failed_state = job->current_state;
+  job->failure_report->msg = strdup(report_message);
+
+  job->current_state = VIETER_JOB_FAILURE_STATE;
+
+  return vieter_job_queue_ok;
+}
+
+int vieter_job_queue_rlock(vieter_job_queue *job_queue) {
+  return pthread_rwlock_rdlock(&job_queue->lock);
+}
+
+int vieter_job_queue_wlock(vieter_job_queue *job_queue) {
+  return pthread_rwlock_wrlock(&job_queue->lock);
+}
+
+int vieter_job_queue_unlock(vieter_job_queue *job_queue) {
+  return pthread_rwlock_unlock(&job_queue->lock);
+}
diff --git a/src/job-queue/vieter_job_queue_internal.h b/src/job-queue/vieter_job_queue_internal.h
new file mode 100644
index 0000000..99ecab8
--- /dev/null
+++ b/src/job-queue/vieter_job_queue_internal.h
@@ -0,0 +1,19 @@
+#ifndef VIETER_JOB_QUEUE_INTERNAL
+#define VIETER_JOB_QUEUE_INTERNAL
+
+#include "vieter_cat_heap.h"
+#include "vieter_heap.h"
+#include "vieter_job_queue.h"
+#include "vieter_tree.h"
+#include <pthread.h>
+
+struct vieter_job_queue {
+  vieter_tree *tree;
+  union {
+    vieter_heap *heap;
+    vieter_cat_heap *cat_heap;
+  } heaps[VIETER_JOB_STATES];
+  pthread_rwlock_t lock;
+};
+
+#endif
diff --git a/src/tree/vieter_tree.c b/src/tree/vieter_tree.c
index 84a1a26..ca6016e 100644
--- a/src/tree/vieter_tree.c
+++ b/src/tree/vieter_tree.c
@@ -114,3 +114,15 @@ bool vieter_tree_validate(vieter_tree *tree) {
   return vieter_tree_node_get(tree->root, vieter_tree_node_black) &&
          vieter_tree_node_validate(tree->root, 0, expected_black_nodes);
 }
+
+int vieter_tree_rlock(vieter_tree *tree) {
+  return pthread_rwlock_rdlock(&tree->lock);
+}
+
+int vieter_tree_wlock(vieter_tree *tree) {
+  return pthread_rwlock_wrlock(&tree->lock);
+}
+
+int vieter_tree_unlock(vieter_tree *tree) {
+  return pthread_rwlock_unlock(&tree->lock);
+}
diff --git a/src/tree/vieter_tree_internal.h b/src/tree/vieter_tree_internal.h
index 1214572..037345c 100644
--- a/src/tree/vieter_tree_internal.h
+++ b/src/tree/vieter_tree_internal.h
@@ -1,11 +1,13 @@
 #include "vieter_tree.h"
 #include "vieter_tree_node.h"
 
+#include <pthread.h>
 #include <stdbool.h>
 
 struct vieter_tree {
   uint64_t size;
   vieter_tree_node *root;
+  pthread_rwlock_t lock;
 };
 
 /*
diff --git a/test/cat-heap/test_cat_heap.c b/test/cat-heap/test_cat_heap.c
new file mode 100644
index 0000000..d415198
--- /dev/null
+++ b/test/cat-heap/test_cat_heap.c
@@ -0,0 +1,52 @@
+#include "acutest.h"
+#include "vieter_cat_heap_internal.h"
+
+#define TEST_SIZE(cheap, size) \
+    TEST_CHECK(vieter_cat_heap_size(cheap) == size); \
+    TEST_MSG("Size: %zu, expected: %lu", vieter_cat_heap_size(cheap), (uint64_t)size)
+
+void test_init() {
+    vieter_cat_heap *cheap = vieter_cat_heap_init();
+    TEST_CHECK(cheap != NULL);
+    TEST_SIZE(cheap, 0);
+    vieter_cat_heap_free(cheap);
+}
+
+void test_insert() {
+  vieter_cat_heap *cheap = vieter_cat_heap_init();
+    TEST_SIZE(cheap, 0);
+
+    void *data;
+
+    for (uint64_t i = 50; i > 0; i--) {
+        vieter_cat_heap_insert(cheap, "cat1", i, (void *)i);
+        TEST_SIZE(cheap, (uint64_t)51 - i);
+
+        data = 0;
+
+        TEST_CHECK(vieter_cat_heap_peek(&data, cheap, "cat1") == vieter_cat_heap_ok);
+        TEST_CHECK_(data == (void *)i, "%lX == %lX", (uint64_t)data, i);
+    }
+
+    for (uint64_t i = 50; i > 0; i--) {
+        vieter_cat_heap_insert(cheap, "cat2", i, (void *)i);
+        TEST_SIZE(cheap, (uint64_t)101 - i);
+
+        data = 0;
+
+        TEST_CHECK(vieter_cat_heap_peek(&data, cheap, "cat2") == vieter_cat_heap_ok);
+        TEST_CHECK_(data == (void *)i, "%lX == %lX", (uint64_t)data, i);
+    }
+
+    vieter_cat_heap_free(cheap);
+}
+
+
+TEST_LIST = {
+    {"cat heap init", test_init},
+    {"cat heap insert", test_insert},
+    /* {"heap insert random", test_insert_random}, */
+    /* {"heap pop", test_pop}, */
+    /* {"heap pop random", test_pop_random}, */
+    {NULL, NULL}
+};
diff --git a/test/job-queue/test_job_queue.c b/test/job-queue/test_job_queue.c
new file mode 100644
index 0000000..3187cda
--- /dev/null
+++ b/test/job-queue/test_job_queue.c
@@ -0,0 +1,23 @@
+#include "acutest.h"
+#include "vieter_job_queue_internal.h"
+
+void test_init() {
+  vieter_job_queue *queue = vieter_job_queue_init();
+  TEST_CHECK(queue != NULL);
+  vieter_job_queue_free(queue);
+}
+
+void test_job_path() {
+  vieter_job_queue *queue = vieter_job_queue_init();
+  TEST_CHECK(queue != NULL);
+
+  vieter_job *job = vieter_job_init();
+  job->next_scheduled_time = 5;
+
+  vieter_job_queue_free(queue);
+}
+
+TEST_LIST = {
+  {"job queue init", test_init},
+  {NULL, NULL}
+};